the car: 95 a4, performabuilt 4l60e, performabuilt 3200 stall convertor, new tr6's, new plug wires, new msd opti, msd coil all within the last 1000 miles. new o2's within the last 1500. also has lt headers with a bullet dumped off of the y-pipe, gears, elbow and cai

the problem: car has a bad vibration under a load, most noticeably around 40 mph once the convertor has locked up. at first i mistook it for a misfire and found a burnt plug wire which didn't fix the problem when replaced. also fix a few vacuum leaks. i call it a vibration but it is not consistent, sometimes it won't do it until you put it under more of a load and sometimes you can literally feel it stop and start. i know my way around my car pretty well and cannot figure this out. went to the track to gauge how bad it is and my mph is VERY low for what it has done before (95 compared to 102). it has thrown a code for each o2, but not at the same time. also threw an EVAP code and the idle is high but will return to normal after a second or 2 with a quick rev

i am at a loss. i'm sick of the thousands i've put into it hoping to fix this problem. i'm almost ready to take it to a shop and make it their problem

 

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Instead of investing $K's in parts why didn't you invest some money in a real time data scanner to look at the data coming into the PCM??????

Why would you change the convertor if you hadn't changed the gears or the cam????

Or is that some of the information you left out and now we have to try to squeeze the rest out of you??????

You have LT's and get an occasional O2 code. So it begs the question, have you looked for burnt wires? Have you tried the car with one of the O2's unplugged to see what happens to performance then??????

Too many questions no enough answers.

 

itSSlowZ28:
Is it possible that you've got a bad injector or bad injector connector or the connectors on 2 injectors crossed?

 

sorry, edited
i have driven it around with a scanner hooked up and the only real reading we have been able to find that seems odd is that one o2 was reading lean. which one it was changed when the code changed to the other. new o2's with extensions. hadn't thought to unplug one or the other, but the o2's only affect the performance of the car in closed loop correct. it does it hot or cold. i've searched the entire engine bay for burnt wires, did not find any other than the burnt plug boot that i replaced

the convertor was changed because my stock trans lost 3rd and 4th and performabuilt had a great deal going on the package, plus its a nice performance addition. and in my first post i stated it does have gears, 3.42s to be exact
i am going to pull off the fuel rail in a couple hours and prime the car to see if one is leaking clogged. nothing involving the injectors or intake mani has been removed in well over a year. is there a way to better test the injectors while driving?

 

went to double check all of my vacuum lines and found a loose injector connector on #7. plugged it back in, double checked all of them and now the car runs great!