At high rpms right before it trys to change gears it makes a back firing sound under the hood and it doesnt shift till i let off the gas then get back on the gas. It does it around 4700-5000rpm and im not sure if its the rev limiter or the tranny.. At WOT the car never shifts because it will make that sound and I will have to let off the gas to shift.

Example, 1st gear, Doing WOT till 4500rpm the car makes the sound and the car slows down automatically, i let off the gas and i get back on it again but it hasnt shifted yet and makes the noise again. So i have to let off the gas AGAIN and let it shift before i can get back on the gas again.

What is it? Is it the tranny messing up, or is it the rev limiter hitting and just taking to long to shift?

Also, its time for a new opti-spark for me, how much are they?

95'z28 A4

 

Its defenitly not the rev limiter since it happens at 4500 RPMs...

 

Had this problem too...worked its way down to happening at 3000 RPM's. Had to get the coil wire replaced..it was fried. Runs perfect now

 

I have a 93 Z with an A4 and am currently having the same problem. Is it the optispark?

 

Alright so its not the rev limiter, i planned on replacing the ignition coil soon so maybe that would solve my problem? Im just afraid my transmission is ****ing up?

I also plan on replacing the opti, how much do they cost?

 

What year is your car? Thatll have some effect on the price. Check your plugs, wires, and coil. How does your tranny fluid look? Is it burned?

 

I thought it was my trans too...took a ride with the mechanic and the first thing he told me was that it was an electrical problem...definetly not the trans. I hope this is your problem, it cost me $100.00. Better than fixing a trans problem.

 

Alright well i'll go ahead and replace the coil, MSD coils cost just under 50 bucks, why did it cost you $100?

Thanks

 

It cost me $100.00 because The car stopped going above 30MPH (found out trying to merge onto the Garden State Parkway) at about 1 PM and I absolutely needed the car done by like 4, so the mechanic rushed the job and had it done for 2:30. At that point I had to have the car back so it didn't bother me.

 

lol i see

 

Hey, I have this exact same problem (I know this is an old thread, but I was searching for it). even like 9/10th's throttle it shifts perfect and nice and tough, but at wot, it makes that back fireing popping noise (which I thought was the car bumping the rev limiter) and sometimes I have to let off twice to get it to shift as well. it makes it a pain in the *** to go good, and is pretty embarrasing (looks like a retarded monkey driving a stick). So its confirmed that this is the ignition coil? I just started having this problem after installing the intake/exhaust, is it because its revving higher now? Can someone point out like exactly what I need to buy at jegs or summit or something? much thanks in advance.

 

At mid/high rpms, the coil and coil wire are suspect. Since you are doing a wire, check the rest of the plugs and wires while you are doing it. If one is bad, unless it it new and burn't, you may as well change them out for new ones and reduce your exposure to another problem next week.

The other thing is to make sure your transmission is full of fluid and make sure it isn't burn't or dark. Many people overlook servicing their transmissions.

 

ah this is an old post... but yeah it was my coil wire.... i took it off and all the white crap fell out, it was corroded to hell. My coil connector rod thing was like staind with that white crap... i just got a wire brush and got most of it off.... car runs really good after replacing the coil wire

 

I changed the tranny fluid and filter, and the plugs about 2 months ago, so I think i'm alright there. What exactly is a coil wire, how much is it, and where can I get one?

 

It connects from the Top right of the optispark to the ignition coil. You can get them at any GM dealer or gmpartsdirect.com they go for about $25 bucks