Firechicken

I have a 98 Z28 A4 with Mac's ORP, 3200 Vig, and a lid. My air system and egr has been removed and deleted. The car will only do this on warm starts. After I start the car It will run and idle fine until Iput in drive and push the gas. Thats when it allways does it. It will stumble, and pop, and try to die. This will last about 3-4 seconds then it will spring back to life and run fine.
Any ideas?

Jeff

Cal

iTrader: (1)

When did this problem start? Was it when you put the cam in? I think poping means you are too rich.

Firechicken

No, I allready had the cam in. It started after I removed the air and egr systems. But I don't see how that could cause this. Also I've removed the cam to see if that was the problem and It still does it.

Any more ideas?

98TAauto

iTrader: (2)

did you delete all the egr SES codes and etc? I know when i had EGR and it went bad my car woul not idle in gear at stop lights. All from a bad EGR... glad I deleted it 2 years ago now

Firechicken

Im sure it was all deleted. Besides It has been off the car for about a month now and I have not seen a ses light. I was thinking It could be a sensor of some kind. Maybe a O2 sensor.

JaSSon

iTrader: (11)

Firechicken mine does the same thing exactly. I can not figure it out. ive changed fuel filter, plugs,even put in new fuel pump(Walbro 340). I thought it was water in gas and have removed and cleaned my tank 4 times. I never get any ses lights and Thunder has tuned my car. Im begining to think it is vapor lock due to the fact it happens only when the car is warm. I did notice how close the header is to the fuel line on drivers side. I am going to wrap those lines and see if that helps. Ive already done the lines under the car where they cross the exhaust. Please somebody chime in and help us out, Jason.

DailyAluminumBlock

How long does this last? If it is only for approximately 15 seconds after a warm start then it probably can be solved by adjusting your volumetric efficiency table in ls1 edit. Just multiply values from 400 rpm to 1200 rpm by 70-50% and it will make your warm start problems go away. It made my warm and cold start problems go away but I'm also running a 224 110lsa cam.

JaSSon

iTrader: (11)

Its not that long after start up. Ill start the car, pullout of my driveway and 2 or 3 seconds down the road it will spit and sputter for a couple of seconds and the it goes away. Some times i put the car in neutral and give it a pop and it evens out.Some times it worse than others on the same day. Also this happened last year then it went away for a few months and then it just came back. I know its not the tuning cause my car has been tuned for awhile and no problems. I had it tuned with just boltons and then again with cam at Thunder. Please someone help this is driving me crazy. Jason

Firechicken

I've found something that might be the problem. I had the car idleing this morning and I was checking to make sure that all the plugs on the TB, and MAF were snaped in tight. When I first touched the MAF plug the car stumbled and almost died. So I gave the wires a little wiggle and sure enough everytime I wiggle the wires the car will try to die. I think It's either a bad conection in the plug or the wire itself is almost broken inside the insulation from the plug being removed and installed so many times.

JaSSon

iTrader: (11)

I also checked that this morning too, but in didnt help and I popped an ses this morning and will go to AutoZone to see what it is. Hopefully whatever it was finally gave out. Did the wire problem fix you car? If so let me know and I canlook at the plug more closely. Thanks, Jason

JaSSon

iTrader: (11)

No dice on the ses light it was a "Idle too high" code. Got to thinking about the MAF and went down the road and borrowed my buddies off his 98, car acted up with that one too. Im at my wits end. Does anyone have a clue? Someone has got to have had this problem before. Jason

Firechicken

Do you think it could be a o2 sensor going bad?

JaSSon

iTrader: (11)

I read that other post also and his problem sounds familiar. My car has acted up after sitting in bank line too. I dont have any way to ckeck the O2s out. I dont mind going to buy them but want to know thats what it is.

Firechicken

Looks like we need to get are hands on a Tech 2.

JaSSon

iTrader: (11)

Im thinking its the drivers side O2 sensor. Got to looking under car noticed the wire on sensor was pinched and running close to header at 2 points. So I got it out of a bind and rerouted it and car started acting real good so far. Its barely acted up on warm starts if it does at all. Im putting new Delco sensor on tuesday along with some new plugs and I hope this is it.