My car (1995 Z 28) runs great in closed loop, but in open loop it starts knocking severely if you give it too much gas. This occurs in all six gears. Any help would be appreciated.

 

Define "knocking" so people will know what you mean.

 

I am sorry, spark knock. Any load that is put on the engine, even minor will cause this.

 

how are you determining this? Do you have any scanner software (i.e freescan, datamaster)? If you do, log the car, and send me the file to Deenasty83@comcast.net I will take a look, and see if I see anything...Thanks..Also please mention in the e-mail what mods have been done to the car..