Would a bad O2 sensor cause the car to stumble under light load? Hit WOT and it clears right up and the car runs great.
Would any other sensors going out that can cause this type of condition? Maybe a bad coil?
J

 

yes, loose wire or fouled plug could also cause that

 

You should do a run with HPTuners and scan for misfires on all cylinders, and watch your O2s.

 

Will do, but it will have to wait as the rain is out to get me, all freakin week. I think it might be a leak in the exhaust, prolly on the driver side header because we were tugging on that thing pretty hard the other day. It might have cracked it somewhere...the headers are pretty old From the searches I ran this seemed to be the problem when the car starts stumbling and stuttering but runs like hell at WOT.

So I'll check that and my O2 sensors. I'll also scan with HP tuners once the weather clears up.
Thanks.
J

 

I have been messing with my throttle cracker, airflow vs. TPS, and running airflow this morning and realized that I have been making what I think is a big mistake. I think *some* problems during cruise may be caused by having a running airflow that is not flat across your engine operating range (especially with a low-temp thermostat). I was noticing weird jumps in IAC count at cruise, and I think that this may have been a big contributor. Just something to think about while we are trying to fix this problem. Also, I threw quite a few degrees of timing at my advance tables up to about 2200 rpms and .24 g/cyl, and it appears to be keeping takeoff bucking under control. I am still messing with it. I really need to take it for a good stop-and-go drive on I-95 during rush hour. That is the takeoff bucking test.

 

Cool, thanks for the info, but I really don't think this is tune related for the simple fact that I went back to my base tune from my track tune and nothing changed. The car never acted this way on my base tune and I've been running that one forever. I did a lot of exhaust work prior to taking the car to the track so I'm sure I have a leak at a flange or collector and its skewing the O2's, or I broke a valvespring at the track I'll find out but its still freakin raining here....I need an indoor garage already.
J

 

I am not following. Are you saying your car does this now, no matter which tune you put in, or your old tune does not surge?