Car's vibrating under acceleration

[rogerzr1]

Ok, so we just replaced the plugs, coil packs, and plug wires on my red 91. Took it out a couple of times and it ran GREAT! I took it out a couple of days ago and noticed some hessitation and vibration when under hard acceleration with the power key on. I turned the power key off and got on it hard and there was no hesitation or vibration(it ran fine).

We noticed when we had the plenum off that it looked like it had some different injectors- meaning some might be originals some not. Does it sound like I have and injector problem on the secondary side?

Thanks, Roger

[tomtom72]

Roger, I have to agree with your theory. If some of the secondaries were changed and some were not then the OE ones could finally be dying from the alcohol.

You are not getting a SES light winking at you when you're hard at it in Full Power mode are you? It may not set a DTC, but rather just lean enough to flash the DTC for Lean....I forget the number. I think it's in the 50's but not sure.

I would also throw a fuel pressure gauge on it, or wait till it's cold and start it up with the FP1 fuse pulled out to see if the secondary pump is at least running. I would still do the KOEO fuel pump test to verify that both are giving the proper psi to be sure.


Tom

[rogerzr1]

Originally Posted by tomtom72

Roger, I have to agree with your theory. If some of the secondaries were changed and some were not then the OE ones could finally be dying from the alcohol.

You are not getting a SES light winking at you when you're hard at it in Full Power mode are you? It may not set a DTC, but rather just lean enough to flash the DTC for Lean....I forget the number. I think it's in the 50's but not sure.

I would also throw a fuel pressure gauge on it, or wait till it's cold and start it up with the FP1 fuse pulled out to see if the secondary pump is at least running. I would still do the KOEO fuel pump test to verify that both are giving the proper psi to be sure.


Tom

Tom,
Thanks for the information. I will try and get a fuel pressure gauge on it to see if that might be the problem. I am not in a big hurry since it is getting hot down here in GA.
RM