car surges and shakes at 1/4 throttle(don't think its compressor surge)


Well-Known Member
Jun 16, 2001
i'm having a strange problem at part throttle. When ever im in 1st gear and go lets say 1/4 throttle and get 10 psi or so, the car bucks and stutters until i give it more gas and it smoothes out. It does it at the latter rpms of 2nd and 3rd as well. WOT is fine as well as a little less throttle than 1/4(normal driving). It really doesn't act or feel like compressor surge, but more like when ya blow an intercooler hose off and the car bucks and chugs until you get enough throttle into it to blow past the leak. I have changed plugs, new wires, it has a new coil pack, switched modules with a known good one, changed fuel filters, swapped to a different LT1 sensor, new 02 sensor, PCV is new, and I've sprayed everywhere for leaks and double checked all my intercooler hoses and checked all the grounds. What am I missing?
My BLMs move around a bit but stay in the 120s, integrator is usually around 126-130, IACs are 000 at idle when warmed up, MAT sensor reads fine, MAFs are around 4-6.
The only weird thing i can think of is that recently my car started to like lower fuel pressure settings, its at 38 line off, and running 16.5 psi with no knock even in overdrive on 93. My car used to like 43-44 or so but i started fouling plugs and running crappy. The EGR works fine as well, and nothing else seems to be a problem. I'm running the wastegate tuner style as well now because my solenoid was allowing creep in the upper rpms of 3rd. Sorry for the length, just trying to provide a lot of info:D
No, the cat is gutted, ATR headers, ATR 3" DP, and 2.5 SS ATR duals all the way back. Could the puck be sticking, never had one stick so im not sure of what it feels like.
This sounds simular to a problem I had once. Vib like you describe turned out be the converter was vibrating when locking and unlocking. I had just had the trans rebuilt and a new converter installed. At first I thought it was the torbo, installed a rebuilt one but no change. Changed converter and it was fixed. Have you checked?
I've unplugged the TCC solenoid for a run and no change, TCC locks up normal at 45 and thats about it. thanks though
Does it do this only after the car is hot? I've been chasing this one for a while now.:rolleyes: :mad:
no mostly when its cold actually, i usually don't get on it unless ive been driven for a few mins, but today i let it idle and warm up and drove it around the block, then hit it in first gear and it bucked and jolted at WOT, once i got some boost into it a few more times it seemed fine again at WOT but back to the usual bucking and jolting at part throttle:rolleyes:
Originally posted by T- Type Tim

Man this post came out of nowhere haha. I think i remember the problem turned out to be my settings on the MAF translator. I had it on 3 for WOT fueling and the translators idea of WOT is a lot different than your foots, so it was pooring fuel in there causing the surge at little throttle