Ugh!!! I'm at a loss. I've tried everything on this bucking, and nothing seems to work. The car is in OL, w/ STFT activated. I dropped the spark in the cruise areas 2000rpm and down low, and 0.36g and lower to about 15 degrees. It bucked worse and worse as I dropped the timing. So I did the opposite, I went up, it seemed to get a little bit better, but still bucked. I went as far as 45 degrees and nothing seemed to improve. The spark does not jump around when its bucking, IAC stays steady, IPW fairly steady. I even used VCM controls to lock onto spark and maxed it out at 50*'s Nothing.

So here is what I have brought it back down to. Seems to of helped the low end grunt when getting into gear and going. Still have the occasional dip down low in rpm, so I increased the spark in that area too.

 

Did you zero out the throttle cracker? Bucking is typically because the motor is trying to go faster without any throttle application, which means either spark or IAC is too high. As mentioned in other threads, I zero'd out the throttle cracker for 1000 and 1600rpms.

 

Yep, throttle cracker is all 0's except for 1000 and below.

The IAC count stays fairly steady when it's bucking and follows desired IAC.

40mph, 1600rpms, IAC = 120 when bucking.

 

Hmmmm. You won't necessarily see the IAC fluctuating. Too much air is too much air regardless. Like I said, you most likely have either too much timing or too much air (or both).

 

Here is my IAC settings, they are basically stock from the 02 program. Couldn't even tell you how to mod it as I've never fooled with this table before.

 

I'm talking about the throttle cracker airflow table, which I don't think you have open in that picture. It should be a table plotting MPH vs. RPM and what I was suggesting was zeroing out the 1000 and 1600 RPM cells in that table. The table you have open appears to be the IAC Effective Area table, which tells the PCM how much air is allowed in for each step. You don't want to mess with that table.

 

Ah, okay my bad. Yes, the throttle cracker table only has the 400 and 1000rpm tables filled in with 1.00 for 400rpm, and 0.50 for 1000rpm.