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Throttle Body Replacement / Cleaning Intake & Boots
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Pelican Technical Article:

Throttle Body Replacement / Cleaning Intake & Boots


3 hrs






Torx driver set

Applicable Models:

Porsche 986 Boxster (1997-04)
Porsche 986 Boxster S (2000-04)
Porsche 987 Boxster (2005-08)
Porsche 987 Boxster S (2005-08)

Parts Required:

New o-ring or idle control valve gasket

Hot Tip:

Remove the throttle body and let it soak in carburetor cleaner overnight

Performance Gain:

Smoother running engine

Complementary Modification:

Replace intake plenum boots
101 Performance Projects for Your Porsche Boxster

This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.

The Boxster throttle body is a precision piece of equipment that is subject to a rather harsh environment.
Figure 1

The Boxster throttle body is a precision piece of equipment that is subject to a rather harsh environment. After years of reliable service, the throttle body may become dirty or clogged, which may result in lowered performance. You may find that there is a lot of built up dirt, particularly if a previous owner didn't change the air filter too often (Pelican Technical Article: Air Filter / Pollen Filter Replacement). Instructions on how to access the throttle body are detailed in Project 83 (starter replacement). Remove the throttle body (yellow arrow) from the intake plenum and then take it over to your workbench and clean it out using some carburetor cleaner. Run lint-free cloths through all of the passages and make sure all the dirt and debris is removed. The blue arrow shows the intake plenum boots that should be checked for cracks and/or replaced after many years of use.

This is what your throttle body should look like after you've finished cleaning it.
Figure 2

This is what your throttle body should look like after you've finished cleaning it. Shown here is the early-style cable throttle with the idle control valve (green arrow). This valve controls the air that passes by the throttle: if it's clogged you will get erratic idle and warm up problems. Be sure to use a new gasket when you remount the idle control valve to the throttle body. With the throttle body completely clean, remount it to the intake plenum using a new rubber gasket (yellow arrow, inset photo).

Clean out any oil and debris from the inside of your intake plenum, and replace the rubber hoses / boots if they are old or cracking.
Figure 3

Clean out any oil and debris from the inside of your intake plenum, and replace the rubber hoses / boots if they are old or cracking. This photo shows the inside of the intake plenum on my Boxster project car, which had a disastrous engine failure. Those small pieces of metal that you see there are leftover piston rings! Normally, you will only find oil and gas residue in the intake plenum. If your air-oil separator has failed, then you will indeed find plenty of excess oil in here and also coating the throttle body that needs to be removed.

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Comments and Suggestions:
Capank Comments: My 2000 Boxster starts great from a cold start then sometimes after its warm it starts to fluctuate between under a 1000 rpm and above a 1000 rpm, at this point its still drivable but could stall. now and again it goes in to limp mode and I have to stop the car and restart the engine this usually works and the car runs fine again. Any Idea's what this could be?
September 15, 2016
  Followup from the Pelican Staff: Could be a vacuum leak or an issue with idle control. I would start by checking for vacuum leaks. If no leak is found, check the idle valve. - Nick at Pelican Parts  
Cornontherob Comments: My throttle cable is currently on the throttle body, and I need to remove it for engine removal. It's off of the spring mechanism, but the cable itself goes through the throttle body, how do I get it out of there? It looks like a black plastic square on it, but I don't know if that's something that can break easily
January 31, 2016
  Followup from the Pelican Staff: What vehicle are you working on? - Nick at Pelican Parts  
HRA Comments: Thanks Nick! Appreciate your comment.
November 19, 2015
  Followup from the Pelican Staff: No problem. Glad to help. - Nick at Pelican Parts  
HRA Comments: Is the following part designed for a Boxster S 2000?
Throttle Position Switch, Brand: Bosch 2000 Porsche Boxster S Convertible, Part #: 996-606-116-00-M14
My car is factory equipped with the following Throttle Valve Assembly Part #: 986-605-115-01-M114
Appreciate for your help in this subject.
November 13, 2015
  Followup from the Pelican Staff: If the part numbers do not match, I would say no. I’m not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts
Sean Comments: I have a 2000 Boxster S. The car starts fine and idles. When the gas pedal is depressed nothing happens. The MAF was unplugged while the car was running and the RPM did increase briefly. The AOS was replaced about a 6 months ago. Just recently had the rear axles, an engine mount and the oil filler tubes replaced. Any thoughts?
May 26, 2015
  Followup from the Pelican Staff: Your car needs to be scanned for fault codes. Sounds like a throttle fault. - Casey at Pelican Parts  
Sean Comments: I have a Porsche Boxster S 2001, 31000 miles, just today when I am at a stop light for example and idling the engine seems to be revving itself. It drops below a 1000 revs and then goes up to a 1000 revs on its own. It does not idle at a constant state. Any advice what this is and what to do?
May 7, 2015
  Followup from the Pelican Staff: Have you already cleaned the throttle body and allowed the throttle to reset? If so it could also be a vacuum leak or bad air oil separator. Check the intake plenum for oil seeping from the rubber rings that connect the two sides of the throttle body. That is an indicator of a possible AOS failure. Those would be my first three checks if I didn't have access to a scan tool which can show you fuel trim data. - Casey at Pelican Parts  
bobatious Comments: Answer to Dan's question - "What is torque spec of four throttle body bolts?":
These are M6 8.8 bolts - max torque of bolts is 10 ft/lbs. Porsche down-specs the torque of this application to 7 ft/lbs per porsche service manual, no spec given in Bentley. This system is described in the fuel/exhaust section of Porsche service documents.
April 6, 2015
  Followup from the Pelican Staff: Thanks for the input on this one. We appreciate the help.
- Nick at Pelican Parts
toddy Comments: I have a 2003 2.7l boxster, when setting off from cold changing gear from first to second is very stiff until the engine is up to temperature then all is ok. Wondering if anybody else has the same problem.
March 22, 2015
  Followup from the Pelican Staff: Sounds normal. I have to ask, what temp? Winter cold temps or summer cold temps? - Nick at Pelican Parts  
Dan Comments: What are the torque spec for the 4 throttle body bolts? Thanks.
August 7, 2014
  Followup from the Pelican Staff: I don't have them handy. I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
Rick Comments: Changed the coolant tank WOW and during the process of replacing the coolant my gas pedal is hard to press down and then goes full throttle, could I have down something when replacing the hoses.
July 2, 2014
  Followup from the Pelican Staff: Sounds like a vacuum hose is knocked off. Look for a large vacuum hose that is disconnected. - Nick at Pelican Parts  
Glrd83 Comments: My 1998 boxster has an issue where it run and drives great, then on Once it warms up the car will deveolp a dropping idle at a red light to the point of almost stalling, and sometimes a stall. What could be a good place to start to get this fixed, no CEL or codes.. cable throttle car. Coil packs are good new plugs, air filter ect. When it does drop idle it goes from 800 to 150-200 Rome then goes right back to a normal idle for about 20 seconds and does it again. Then sometimes not at all......
March 25, 2014
  Followup from the Pelican Staff: The idle valve may be sticking. Try cleaning it. - Nick at Pelican Parts  
Niko Comments: Finally I had time yesterday to remove the throttle from the engine it was pretty clean. I still cleaned is with throttle spray cleaner, air flow sensor cleaner for the electrical connections. Also I cleaned all ducts, hoses and tubes including the air oil separator with throttle cleaner spray. Make sure when putting everything back its a sealed system.
The car runs great now the only thing I have to do is take the car to a mechanic as the engine light comes on to re program the engine management system. The car goes like a dream now bar the warning light.
February 23, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
Niko Comments: I need some help, i have a 2001 Porsche Boxster 2.7 litre.
When i start it cold it starts with slight rough idle movement.
Then when i'm accelerating it studders and if i keep the accelerator at the same pedal speed the car pushes forward and backwards...please help me
January 22, 2014
  Followup from the Pelican Staff: Sounds like it could be an engine misfire. Have you checked the DME for fault codes? - Nick at Pelican Parts  
John Galt Comments: My 2006 Porsche Boxster recently starting making a sound like it’s gasping for air when I hit the accelerator pedal. It happens all the time, regardless of whether the engine is hot or cold. It happens regardless of whether the vehicle is in gear or not, regardless of whether the vehicle is in motion or not, and regardless of whether I am on the clutch or not. All I have to do is quickly hit the gas pedal at any point and it will make the sound, whether I’m stopped at a traffic light or accelerating while already in motion. I removed the engine cover to check the snorkel and air filter. Everything is tight. I used an automotive stethoscope and it sure seems like the noise is coming from or right around the throttle body. Could this potentially be an issue with the throttle body or is the noise just seem like it’s originating there since that’s where the air flow is being controlled? Here is a video of the sound on YouTube: - Thanks in advance for any helpful thoughts!
November 10, 2013
  Followup from the Pelican Staff: This sounds like a vehicle with an exposed air filter. For example a cold air intake. I would double check that the intake air housing and ducts are all properly connected. - Nick at Pelican Parts  
Aussie Paul Comments: Hi there
I have a 1999 2.5 boxster
There is cruise on the indicator assembly and a light in the instruments but I think there is nothing on the motor to actuate it. the motor has been changed over prior to me owning it
Do you have any photos of the assembly on the motor and some indication of cost for parts
Kind regards
October 28, 2013
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you out with the cost.

The cruise control unit with the drive motor is mounted to a bracket above the accelerator pedal.

- Nick at Pelican Parts
RickR Comments: Just replaced the AOS, thanks for the article on that, although one of your links for the part went to the wrong AOS. Now I'm getting CEL and codes P0410 and P1411, Secondary Air Injection. Some research shows that it could be the Air pump, which works on my Boxster, check valves or vacuum lines inside the Intake Manifold. Another symptom is the engine tries to stall when coming to a stop light, but then fixes itself and idles just fine. Is it all related?
September 11, 2013
  Followup from the Pelican Staff: The secondary air would not cause a stalling issue. I would run the sceondary air test using a Porsche scan tool. When the secondary air is activated, the front oxygen sensors should see an initial lean condition. This is a good way to check it. - Nick at Pelican Parts  
MarkG Comments: Hi

i have taken the throttle body off... but have the same question as the post before. What does the rear pipe between the plenums with baffel in it do, mine seems oily on the outside .. can they cause airleaks ?

Regards Mark
June 21, 2013
  Followup from the Pelican Staff: The rear pipe is for the variable intake manifold runners, varioram. It changes the air flow of the intake manifold depending on engine RPM. - Nick at Pelican Parts  
nick Comments: what are the two pieces that are being showing with the blue arrows? i was taking them off the other day to clean my enging n one has a pump that operates the baffle on the inside of the tube n i broke it on accident.... there is also a hose coming off of it and have no idea where it goes needd helllpppp plz.....
April 7, 2013
  Followup from the Pelican Staff: The blue arrows point to the intake manifold plenum connecting pipe insulators and clamps. - Nick at Pelican Parts  
hens Comments: Hi, i have a problem with my boxster 2,7.
When it is in higher rpm it won't go back to idle. It stays at that RPM or drops really slow, sometimes when i don't push any pedal it even goes higher in rpm. What can cause this problem?
September 16, 2012
  Followup from the Pelican Staff: You could have a vacuum leak or a faulty idle circuit. - Nick at Pelican Parts  
Osio Comments: Hi;
I have a 2000 boxster with 65,000 kilometers which has developed a huge problem.the car was running great when i
shutted down,when i re started it went into limp mode.The mechanic has installed a new throttle body unit and it was running OK. for 5 minutes when shut down & restarted it went in to limp mode again rev only to 18,000 rpm.He said
might be the DME.Before I believe Him and pay a huge amount a money for a DME I like to ask some one to advise me of any other alternate remedy or fix related to this problem
He tells me the car was on the diagnostic machine cleared all the codes end refreshed the DME.The car is still in limp mode he said it could also be in the engine internally.
Please someone save me from this bottomless money pit.
Best Regards;Osio
August 27, 2012
  Followup from the Pelican Staff: If the engine is running a default mode, there will b e fault codes stored. I would scan the DME with a Porache scan tool and start by diagnosing whatever code is present.

If you doubt the diganosis of your mechanic, find one you trust. Ask friends for a recommendation. - Nick at Pelican Parts
Lace Comments: Just cleaned my 2000 Boxster TB. It doesn't take a valve gasket nor intake ring. Instead it has electronics attached which you should leave alone and the ring is built into the intake. The intake is a bear to get back on but w/ a little grease and some strength it gets there. Idle improved alot.
April 21, 2012
  Followup from the Pelican Staff: Thanks for the additional information. - Nick at Pelican Parts  
Sak Comments: Hi, recently my check engine light came on, in my 99 boxster. For several weeks prior to that, my idle was irregular, it would fluctuate, not wildly but enough to notice. It would usually go from 800 to 1200. I attributed this to cold startups, but now am wondering if this could be a possible reason why the CEL is on.
December 7, 2011
  Followup from the Pelican Staff: In order to figure out what the issue is, you need to grab the codes from the car. I have an article on this here: See what codes are showing and then post them in our Boxster forum. - Wayne at Pelican Parts  
Lancair Comments: I have a 2000 Boxster which has the newer electronic throttle built into the throttle body. I'm getting a ODBII code PO507 that is telling me the Idle Air Cotrol is bad. Based on this article I don't think my car has an IAC? Can you clarify? Idle is eratic and check engine light is blinking.
June 26, 2011
  Followup from the Pelican Staff: On cars with the electronic throttle body, the idle air is controlled by the computer opening and closing the throttle slightly. So, there may be an issue with the actual unit, or it may be that it's dirty or clogged. I would clean it first (see the article in our tech articles section on this) and see if that improves the performance. I suspect it will. Also, if it's really dirty or clogged up, keep in mind that this is unusual, and that something odd must be causing the clog. It might be a bad air filter, or a failing air-oil separator. - Wayne at Pelican Parts  
RickE Comments: Thanks for writing back. I took it to a shop a couple weeks ago and they found the oil dip stick tube had a crack and there was a bad relay in the emmissions system. Now it is running great. If I had had the book I might have been able to fix it myself. Will it be out for Xmass?

Thanks, Dave
November 29, 2010
  Followup from the Pelican Staff: Looks like the book will be out in late December 2010 or early January 2011! - Wayne at Pelican Parts  
RickE Comments: Hi,
I am having a big problem with my idle surging up to 3K and back down again over and over. It makes the car very hard to drive when it does this. When the car is cold it starts up and runs like a dream. If I don't shut it off it keeps running fine. If I shut off the engine and restart it I get the wild surging engine. It is like I am depressing the peddle over and over. It will not go back to normal until next cold start. I was going to try cleaning the throttle body and want to order the gaskets as listed above. When I go to the parts for this project page it shows the mass airflow gasket but not the Idle control valve rubber gasket. What is the part number? I have a 2004 Boxster 2.7. Can you think of anything else I can try? Thanks, Dave
October 21, 2010
  Followup from the Pelican Staff: This is typically a mixture problem called "hunting". It's very symptomatic of a vacuum leak in the system. I have an article on checking for leaks right here: As for the gaskets, if they are not listed in the catalog, please give our sales dept a call at 1-888-280-7799 and they can assist you with tracking them down. - Wayne at Pelican Parts  

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