I have a 2000 Z28 that over the past few week has been gradually running worse and worse, eventually got to the point that it could barely get above 45 mph until the engine was warm. Even then when you would stomp on it it would spark knock and hesitate very bad before taking off and wasnt really taking off that hard then. I thought maybe it was because of the headers and was a O2 sensor problem, but when O2 sims didnt fix it off to the shop it goes.
It turns out that my K & N air filter that I had put in a while back had so much oil in it from the factory that the engine was pulling it out of the filter and it had gunked up the sensor wires on my MAF. After the shop cleaned the wires off the car ran like a skalded dog again. But it cost me 55 dollars
Just thought I would share this little experience just incase anyone else ever has this problem. or atleast now everyone can be aware of it.
P.S. it never did get slow enough to get beat by a mustang
