Spark plug foul up

[martingmc86]

I have an 86 GMC Sierra 5.0 with a MSD atomic 1 EFI have had an issue with my spark plugs, getting folded up after a couple hundred miles to get cover in black and truck runs like **** first, I thought it was my carburetor so I decided to swap it out to an MSD atomic one EFI and it runs great but after a couple hundred miles like I’ve said the spark plugs foul and goes back to **** what can it be? I rebuild the distributor and put new pick up coil new capacitor, spark plug module new rotor plugs and new cables and still does the same thing my distributor does not have a vacuum advance it is a ESC ELECTRONIC SPARK CONTROL came out of California, so it had smog regulations

 

[Robert Bare]

First you have to determine if it is too much oil or gas. Plenty of youtube vids can help you.

 

[Ricko1966]

See if your timing actually advances,no advance will foul plugs. Monitor O2 sensor voltage with a multimeter,postcresults. O2 sensor has to be hot to work so monitor hot.