95 T/A A4- I had a problem before when the car would hesitate badly on high rpms... then i changed optispark and it got better but it would then make the motor backfire from the front around 4500-6200rpms, then changed plugs, checked wires, no difference... then changed ignition module and it ran perfect for about 2 weeks.... now all of a sudden it came back... changed module again and put on another coil and same problem...

any suggestions? the car pops very loud from the motor at high rpms but only under wot. sometimes it actually goes away if u beat on it for a little while. But it seems like the problem is getting worse? Is that popping possibly a fuel issue? The car still has a lot of power and although it started popping now it still makes decent power up high. I checked the fuel pressure before and it was around 45 psi at idle, but never checked while driving. Both 02 sensors are new delco's too. where do I begin? thanks for any help.

 

are your spark plug wires hooked up to the correct cylinders? i suggest you check those over. back fire or after fire?

how old are the wires, could they be arching?

 

two of the wires have to be factory but I would assume that they were changed at one point or another before i purchased vehicle a little over a year ago. The rest are a combination of taylor and accel wires because I kept melting wires on the headers... the remaining two are definately not burned... but I suppose could be arcing.... but it comes and goes but lately its just been getting worse all the time only under wot. And yes... all the wires are on the correct cylinder.

 

you sure you dont got a leaking waterpump? ruining your opti?