I went ahead and replaced the 6 year old plugs ( champion truck plugs ) on my 1993 F150 ( 4.9 eng , e4od trans ) with Bosch platinums. The truck was running great before the change but with the change I was getting an occasional stumble and misfire at idle ( close to stalling ) . Otherwise the truck appears to run just fine. I then installed a NEW set of champion truck plugs and again, I still get that stumbling at idle. I then re-installed the OLD champion truck plugs and everything is fine, stumble is gone. The old plugs are pretty badly worn but not too much in the way of deposits. Can somebody explain why new plugs would cause the truck to run so crappy?
- posted
19 years ago