I Have A 91 Z28 That Has Been Running Rough. I Have Changed The Plugs, Wires, Cap, And Rotor , Ive Also Put Full Tank Oh High Test Gas In With Gas Cleaner And Changed Ignition Module. Nothing Changed Does Anyone Have Sugestions.

 

Check your egr valve.A little better idea of when its running rough would help...Accel...cold?

 

Check for vaccum leaks. Also, I know it was running rough before you did all of the work, but check your firing order, you may have them crossed.

Also, I know that when my fuel pump went out, it would work but made it run really bad for a few days before it finally quit working all together. It was kinda odd, they usually just stop working. Did you change the fuel filter? Air filter?

 

IT RUNS WORSE WHEN ENGINE IS WARM-- BUT HAS RUFF IDLE ALL THE WAY THROUGH RUNNING AND DRIVING