Originally Posted by smashpunk68
I Put A New Cap Wires Every 3 Months It Lasts For A Short Time And Starts Little By Little To Get Worse Any Ideas?????????
Start with the simple and replace your Rotor and Cap with OEM or good products. It's common for the spark to jump in your distributor cap at highway speeds with cheap rotor and cap. The best ones for our Vortec engines are the Distributor cap with brass sleeves to keep the spake plugs from arcing, which is causing your misfire.
There is also a breather screen at the bottom of your distributor plate that tend to get dirty causing no ventilation under your distributor cap. Condensation is know to occur promoting corrosion to the electrical lead wire to your ICM and arching between your rotor and distributor cap causing premature failure.
The other thing that would also cause this issue is a worn distributor worm gear and there is to much play causing you to loose your timing at higher rpm's (Arching once more).
Keep me posted and good luck. http://www.accel-ignition.com/
Makes the brass post terminal distributor caps for the issues the Vortec has with arching.