Ramkid53

Ok folks I know someone has probably posted the same issue before, but I just can't find anything relating to my problem. So if you would read my problem and help before I throw tons of money at maybe an easy fix.

The car is a 2002 WS6 A4. It is pretty much stock. The only mods made to the vehicle have been:
1. SLP Lid
2. Magnaflow Catback
3. Electric cutout welded into the magnaflow catback

The problem is this. On a "Cold Start" the vehicle idles decent until the engine temp begins to rise. Once it begins to warm up, the idel gets terrible. It will start bouncing around from the 700-800 RPM range down to 300-400 RPM range. Sometimes it will even completly stall/die. It will restart fine, but the rough idle will remain until the engine has warmed up completly. About 10-15min. After it is warm smooth as butter. I can "Warm Start" all day long without issue. It has not been setting the SES light anymore.

In fact I have been back and forth with the dealership in which I've purchased it for warranty work. Thank god for extended warranties. There isn't an event that I did with the vehicle to cause this. This was the initial reason I took it in for warranty work. They have been able to pull codes before, and ended up replacing the MAF, the passanger side CAT, and Pre 02 sensor on the passenger side. Now according to the dealrship it checks out fine, and they don't see an issue anymore...................Well it seems that nowadays that if there isn't an SES light or check engine light it must be fine. I am not an esxpert, but I know when something just isn't right, and this isn't right. After reading multiple posts here I am going to look for a vacuum leak, and probably replace the IAC valve. Please stop me ahead of time if there is a much easier fix. Thanks for the advice ahead of time.

ghardester

Last time the spark plugs and wires were changed was when?

Ramkid53

Sorry for the delay was taking a final exam online.

I don't know. I bout the car 1 year ago, and have put only 10,000 miles on it. I have a new set of NGK TR 55s ready to go in. Haven't bought new wires though. Do you think that they are a factor since the car is only doing it during the warm up period. I would think that it would consistently do it if they were bad. Will try if necessary though.

Ramkid53

Late school night....Going to bed hoping to get some good input form oyu guys. Thanks again for everyone's help that replies.

ghardester

I really can't tell you if that is the problem for sure. I have just seen so many rough idle/performance issues that are just new plugs and wires needed. A bad wire can connect better when warm or fail more under a load. Since you have the plugs, get new wires, MSG or Taylors, or stock, or what ever and change both. A lot of people skip the wires, but you can't tell just by looking at them if they are good. If that's not it, at least you have done a tune up that you were going to do anyway.

fuseone

could be a iac problem i see it alot in the feild where they never like to use a scan tool to see what some of the stuff is reading or to do any real diag all they really do is is just throw parts at it if it throws a code.

Ramkid53

That is about the way I feel now about mechanics. I did replace the IAC, and NO change. This is some craziness.

I'm going to change the plugs and wires this weekend, and hit a buddies house to throw some random parts at it off his 01 camaro since he is dead in the water right now. We should be able to find the right part that way.

Will keep everyone posted. Thanks for the inputs.

keliente

iTrader: (22)

I do not think spark plugs and wires will fix it (by all means do plugs though if you never have before!).

I think this is due to a failing TPS, or gummed up/dirty throttle body. I'd remove the throttle body and clean it out real well (including the IAC). You'd be surprised how much it may be dirtied from ingesting oil as LS1's do. If that doesn't fix it, I would borrow your friend's throttle position sensor and see if that helps. The TPS may be going bad, but has not had enough bad trips yet to set an SES light.

Ramkid53

The plugs and wires are really just that...because I DON'T know when they were last changed.

I will give the throttle body a good cleaning, and if necessary slave in the TPS. Thanks.

Punisher_ws7

iTrader: (6)

i am having the same problem, i have a scan tool and it has a monitor.. looks like mine is idling well in open loop but as soon as the pcm goes to closed loop the rough idle starts and gets worse until it dies or idles back up and starts over...

I replaced the maf, sparkplugs, coils, wires, and the temp sensor in the air box... i think its a sensor just cant find it...

My sec air inject is malfunctioning not sure if thats the problem tho..

hope this helps you some and i hope to get help off the thread jack too haha...

Ramkid53

No worries. That is what these forums are here for to get everyone as much info/help as possible. Once I get it I will post up the fix so keep looking.

Punisher_ws7

iTrader: (6)

as will i ... thanks.. no luck yet tho

Punisher_ws7

iTrader: (6)

well i replaced my front o2's (deletes in rear).. and now it doesnrt die but its showing a misfire and in closaed loop the "short term fuel trim is like -39.5 and the long term is like -3.5 on bank 1 so i think my problem is either the injector or one of my msd coils.... don't know yet

Punisher_ws7

iTrader: (6)

replaced one of coils on the cylinder that was showing misfire... problem is almost fixed.... gonna drive it and ill update later..

Ramkid53

Sounds like you're almost there. Wish I had a scan tool like that to look at all my stuff. Thanks for your inputs though.

Punisher_ws7

iTrader: (6)

have drove the car past two days and runs alot better... i still think there is something small wrong but the car is drivable now.. take your car to adavanced auto or somewhere with a free scanner and see if it throws a cylinder # misfire... check everything to do with that cylinder... and hopefully it will fix your problem

Ramkid53

Well, I replaced the plugs and wires, and fixed a vacuum leak from the PCV valve, and still nothing. While the car is warming up I am getting a flashing SES light with a P0300 random cylinder misfire. But again once the engine is at operating temp it runs perfect. No miss, no code no nothing. Wierd! I suppose I'll take it in for more warranty service since it is throwing a code now.

Punisher_ws7

iTrader: (6)

you o2 sensors sound like they are not operating properly .. they have heating units in them.. might need to check them

Ramkid53

Okay so they have had it for awhile now, and have replaced a cracked vacuum line for the PCV valve which can make sense, and are also replacing the intake manifold gasket. All of which can cause unmetered air into the engine causing a lean condition. Which would explain the reason for the rough idle, and once the engine warms these leaks are sealing, allowing the computer to properly manage air fuel mixture. We'll see I get it back tomorrow.

Ramkid53

So far so good. It only took a month to get this right. Nothng more than the intakemanifold gasket, and PCV vacuum tube leaking. Car runs great now. Along with all the other parts I've swapped out, it is very responsive to my foot. Love it! I appreciate all the advice I got from everyone looks like the issue has been resolved.