My 98 Z28 A4 is having some sputtering issues from about 60mph on up under WOT. Other than that it seems to run ok. I raced it this weekend at the track and it ran like crap from about 60-100. I ran 14.04 at 99 mph in the 1/4. 60' time was 2.16. 1/8 was 9.09.

The only mods I have are a lid and exhaust cutout. I have not tuned it. It has 78,000 miles. It had 1/4 tank of 93 octane gas when I raced.

Any suggestions on what I should check? I am thinking maybe the fuel filter and plugs? Thanks.

Also I did recently clean the MAF wires with a q-tip and electronics cleaner. Could this have caused the issue?

 

also check plug wires. possibly even a coil pack.
maybe an air leak between the maf & intake?
might double check the maf and see if anything is on it

 

Right with the post above, possibly a coil pack. I had a similar problem. Under normal acceleration everything was cool, but when I went to WOT or close to, it sputtered out. Changed coil packs and was good to go!

 

is there a way to check the coil packs?