ok I have a 97 Z, its been having issues, and i want to fix it soon. some of my sympthoms are, horrible gas mileage like 10mpg/city, seems to be down on power...a year ago i could spin my tires from a stop all the way into 2nd, now I can barely spin 1st with the same tires, (its an A4) and she seems to top out at 120 (100% throttle) rpms get up to 5700, but that might be minus a few hundred rpm as my tach is off + 200 rpm or so, stock 3.23 gears...she has been faster than 120 before when I 1st got it. I do 90% city driving and normally I keep the rpm's under 3000. I have replaced coil, plugs/wires, pcv, fuel filter, o2 sensors,used different MAF, test fuel pressure and its okay, it doesnt drop after shutting car off. I have an autotap and i dont see any codes, no knock or missfires or anything. What do you all think? any suggestions as where to go from here?

 

Are you sure she isn't misfiring?

TTT for ya..

 

have you tried to replace you oxygen sensors? If not give that a try.

 

yep Oxygen sensors were replaced with AC Delco ones. I hooked up autotap and it shows 0 missfires on all 8 cylinders, unless its missfiring and its not registering with the computer. I really am at a lost right now.