Spark plug fouling

[twobjshelbys]

Originally Posted by bobcowan

Fouling plugs usually points to one of two problems: Rich mixture, Burning oil. Be sure to check for the later before working on the former.

If it was running well, and now is not, you have to look for the common denominator. For example, if it was running fine, but now fouling plugs in 1-2 cylinders, look for a problem unique to those two. Like a stuck injector.

Since all of your plugs are fouled, look for something that controls all injectors. The tune could be corrupted - it happens. Reload the tune from a back up.

Also consider that a sensor may have failed. Ford O2 sensors are pretty famous for failure if not installed correctly. Check the calibration on the TPS. Could be something simple, like the vacuum line to the BPS came loose.

Don't panic. Just start going down the diagnostics list until you find it.

Roush does not provide any tools for reloading the tune.

It could also be the MAF... Unlike most cars the Roush 8-stack MAF is unprotected.

Do you have the K&N filters on the trumpets?