1999 996 Idle Problem

[ChilPhil]

I own a 1999 996 Coupe that has been in a local shop for approximately 4 months with this problem. The initial problem was I had the transmission replaced and since then the vehicle will not idle proper. The vehicle will start and run but, not without continually pressing the accelarator. I had the oil separator replaced and the MAF sensor. Can someone please offer some helpful advice. Thanks in advance!

Concerned Porsche Owner

[Loren]

C2 or C4?

Was the transmission a 6 speed or Tiptronic?

[fredkhaz]

I own a 1999 996 Coupe that has been in a local shop for approximately 4 months with this problem. The initial problem was I had the transmission replaced and since then the vehicle will not idle proper. The vehicle will start and run but, not without continually pressing the accelarator. I had the oil separator replaced and the MAF sensor. Can someone please offer some helpful advice. Thanks in advance!

Concerned Porsche Owner

I have the same problem with my 996 tip sometimes .. cleaning the intake helps mine alot

best

fk

[Stefan]

Is it running poorly too or just not idling?

[GOB]

ICV valve?

[ChilPhil]

I own a 1999 996 Coupe that has been in a local shop for approximately 4 months with this problem. The initial problem was I had the transmission replaced and since then the vehicle will not idle proper. The vehicle will start and run but, not without continually pressing the accelarator. I had the oil separator replaced and the MAF sensor. Can someone please offer some helpful advice. Thanks in advance!

Concerned Porsche Owner

[ChilPhil]

C2 or C4?

Was the transmission a 6 speed or Tiptronic?

The tranny is a 6 speed C/2

[ChilPhil]

ICV valve?

Thanks for the input..i'll try it.

[ChilPhil]

ICV valve?

I'll try cleaning/or replcing it. Thanks!

[Loren]

C2 or C4?

Was the transmission a 6 speed or Tiptronic?

The tranny is a 6 speed C/2

Then start by cleaning the throttle body and idle control valve.

[ChilPhil]

C2 or C4?

Was the transmission a 6 speed or Tiptronic?

The tranny is a 6 speed C/2

Then start by cleaning the throttle body and idle control valve.

I just spoke with the shop manager and he says the vehicle isn't presenting any fault codes. Therefore, he would like to swap out my ECU to verify if it's working properly. Please advise!

[Loren]

I would still start by cleaning the throttle body and idle control valve.

That remove them as a variable.

A new DME is about $1500.

[ChilPhil]

I would still start by cleaning the throttle body and idle control valve.

That remove them as a variable.

A new DME is about $1500.

After speaking to the shop manager, I'm beginning to feel that I'm being taken for a $pricey$ ride. It's apparent that when I mention to clean the ICV and throttle body he said that it'll idle by itself some of the time then it just dies out. I really don't believe that he's being honest with me.

[Loren]

I am not trying to dis the shop - I just don't understand why they would not look at the simple more routine cause of that type of problem (which is a dirty throttle valve and ICV).

IMHO - changing the DME would be a last resort.

[LJPete]

I would still start by cleaning the throttle body and idle control valve.

That remove them as a variable.

A new DME is about $1500.

After speaking to the shop manager, I'm beginning to feel that I'm being taken for a $pricey$ ride. It's apparent that when I mention to clean the ICV and throttle body he said that it'll idle by itself some of the time then it just dies out. I really don't believe that he's being honest with me.

Which shop are you taking it to? There are plenty of good shops for Porsches in the DC area.

[logray]

Clean your TB. DO IT NOW. It's about a 1 hour job max (if you're really anal). If this is your car's first time and it is several years old it will improve your idle and throttle response.

What you'll need:

-Chem mask (or do it outdoors on a windy day with a dust mask)

-Carb cleaner (aresol/compressed canister)

-Microfiber cloths (don't want bits of cheap cloth getting in your engine with a regular rag)

-m10 and m13 sockets w/extension or deep and wrench to remove throttle body

-mechanics gloves or disposable latex gloves

-flathead screwdriver to remove air intake hose

-phillipshead to remove idle control from throttle body

I cleaned my 99 C2 996 a few days ago. It had never been done before. With car in sunlight. Removed airbox (1 bolt, ingenious) a few clips, MAF cable, clamp and it's off in a jiff. Next 4 main throttleb bolts, 1 nut, a few clips, a few wires. Push in on the butterfly and the wire comes right out. After this the entire throttle body comes right off - pain free. Away from the car outside on a clean piece of newspaper, liberal application of carb cleaner onto all inner surfaces of body (use mask and gloves), microfiber cloth will remove all deposits after a little soak time and a little rubbing. Wipe dry with clean cloth. Remove idle control with phillips head, spray inside. Wipe clean. Removed a ton of old deposits, metal will be shiny, reinstall all parts.

Enjoy smooth idle and much improved throttle response.

Before I did this idle would fluctuate between 600-800. Throttle was dead until half way down or at high rpms.

Afterwards I had a new car. Stable idle around 690ish. Throttle was much snappier through the entire range.

This has been covered many times before.

BTW I've seen DMEs on ebay for less than $1g, but programming will cost you more. This procedure will cost you $30 tops if you buy all of the tools and cleaning supplies.

[DannyLee]

logray,

Is there a diagram/picture somewhere that points out where these engine elements are?

I'm new to my 996 and wouldn't want to remove the wrong bit (I'm not saying I don't know what engine parts are, it's just that I'm not familiar with the Porsche names).

My throttle is rather flat until half way - I may give the cleaning a try.

Danny

[Loren]

logray,

Is there a diagram/picture somewhere that points out where these engine elements are?

I'm new to my 996 and wouldn't want to remove the wrong bit (I'm not saying I don't know what engine parts are, it's just that I'm not familiar with the Porsche names).

My throttle is rather flat until half way - I may give the cleaning a try.

Danny

http://www.renntech.org/forums/index.php?s...ost&p=64867

[farmer boy]

logray,

Is there a diagram/picture somewhere that points out where these engine elements are?

I'm new to my 996 and wouldn't want to remove the wrong bit (I'm not saying I don't know what engine parts are, it's just that I'm not familiar with the Porsche names).

My throttle is rather flat until half way - I may give the cleaning a try.

Danny

http://www.renntech.org/forums/index.php?s...ost&p=64867

I had a similar problem after changing the starter motor (it involved removing the throttle butterfly) and I inadvertantly managed to replace the rubber hose slightley off centre - this covered what looks like a vaccumm tube and stopped the motor from ticking over although it would start and respond to the throttle ok. I moved it a couple of mm (to uncover the holes) and all was well. Hope this helps - good luck!

[Porsche of Persia]

Did they check your ignition coils?

[Stefan]

For non eGas cars such as the 1999, cleaning the throttle body will almost never affect idle. I don't mean to doubt that cleaning your throttle body will make your car run more smoothly but I don't think it will fix your idle problem.

Since the problem was described as an idle problem, I would definitely start with the idle control valve (ICV). It can be quickly and easily removed.

"Will not idle without pressing the gas pedal" sounds exactly like a stuck ICV.

Cleaning the ICV is an easy DIY. All you need for tools is a Torx screwdriver. It is right on the top of the engine so it is easy to access.