Hey All,

First I would like to start out by saying though this is my first time posting, I have been reading and using this forum for over 2 years now and it has been a life saver time and time again. I finally am at a breaking point and I really need some help attempting to figure this problem out.

I have a 2002 s2k with around 120k on it. It has cat back exhaust and an ACT clutch installed but other than that it is stock. About a month or so ago the car started having a small idle issue. It would stall very rarely when rolling to a stop but I could always fire it back up and it would run fine for a few days then do it again. Over the past month it has gotten to where it stalls almost 50% of the time. When I start the car the idle is fine( if not maybe just a little up and down before steadying out). I can take off and it seems to be running fine but when I start to come to a stop it will either run all the way down to around 100 rpm and then bounce around till maybe idling again correctly or it will just die. If it dies, I can start the car again and it idles fine. As soon as I give it gas, even to just rev the motor a touch, it will die again.
Recently my AC compressor clutch froze up and it fried out. I just removed the compressor today to see if maybe that was causing part of the issue and still the same problem(I am using a shorter belt now that the compressor is gone). I have tried the map whack with no luck. I am not getting a CEL pop either so that is giving me no clues. All vacuum hoses are attached and not cracked or brittle. I changed the plugs about 30k ago and adjusted the valves then too.

I have sense been forced to buy another car as a daily driver but am not yet ready to give up on my S2k. Thanks again for your time and please let me know if I can give you any other details.

Thx,

SED

 

These cars always have some sort of weird idle but the only factors I can see that can contribute to it is:
-TPS
-Try a compression test just to make sure
-O2 Sensors
-Reset ECU
-Fuel Injectors (check to make sure they are clean and no debris is clogging it up)

these are just a few things I can pop off my head at the moment.. Theres a full article on where to start in this situation somewhere around here. So are you saying it wont take off properly, or just idle?

 

I had a compression test done about 15k again and it was fine. I did reset the ECU I suppose when I took the AC compressor out because I had the battery out of the car for several hours( which should reset it correct? ) The O2 sensors would pop a CEL if they were bad would they not? I do have an extension on one of my O2's so my exhaust doesn't pop the CEL. I will check the injectors now.

The car takes off just fine. When I come to a stop, it stalls. Start the car again...idles fine. Give it gas(any amount, full rev or just a tap) then let off, stalls. Start again, seems fine...and repeat = P If I get on the highway...everything runs fine...get off and come to a stop....stalls.

 

Try cleaning the IAC. Could also be a bad tps.

 

Oh, and that^^ The fuel injectors is least likely going to be it, but you never know. They have ways of testing them to make sure it sprays correctly. Could try getting a fuel system clean (the real ones, not the ones you put in the tank) makes your car run freaking scary while its cleaning, but it works. I checked my fuel injectors though after 100k+ miles and they were squeaky clean so. What I usually do when I reset the ecu is just pull the backup fuse for a few minutes, usually works. Do check the IAC like he was talking about, it is common. Good luck bro!

 

Of course it will idle like that if you disconnect the battery anytime. After u connect the battery, let it idle for at least 15 minutes so the ecu can relearn its proper idle spot. Then u should be fine and wouldn't have that stall problem everytime you stop the car at a stop sign or red light. Now if you did the clutch job yourself, did you connect the ground wire at the end of the cylinder head near the firewall cause that can give you some idle issues too.

 

Hey all,

Thanks for all the feedback! I cleaned the IAC really well. The top port was clean as a whistle but the bottom two had quite a bit of carbon build-up. After that I pulled the fuse to reset the ECU and let it idle for about 15 minutes. This did seem to help quite a bit! I drove the car to work today just to check it out and not a single stall!!! Still not holding the greatest idle in the world or maybe I'm just over thinking it cause I've been dealing with this for so long.

Franky,
I did not do my clutch myself this time so I cannot confirm that the ground wire is correctly connected. Where exactly should I look for this? Will I be ale to see it from the bottom of that car if its up on jack stands?

Brandon,

Thanks for the info as I really didn't want to pull the injectors. Though I do seem to still have a bit a rough idle I don't really think its a fuel problem...though I have noticed a little lack of power in the car recently. Could this be a cause if this??

 

I have the same year and mileage as yours, and had the same problems.

Cleaned the IACV like you did, and make sure your plugs are still good. I know you said you changed them 30K ago, but I would still check them none the less, and replace if necessary.

After doing all that, my car idles beautifully.

 

U wont be able to see it at all with the valve cover on. It will have to be remove. Its on the side of the cylinder head facing the firewall in a tight spot. If it's done by a shop, then it's probably good but if not then later down the road, ur speedometer speed keeps jumping up and down and giving wrong speed reading or if ur car just wont start at all, hookup a scan tool to it and see if it will start. If it does start then yeah tat ground wire is loose or came off.

 

How do the plugs look? I had an odd hesitation at take off that was due to my plug gap wearing too large.