Fouling plugs . . . straight pipes and K&N

[JoeVR5]

Hi all,

I have a 97 Ranger 4.0, 2x4, 5spd. It is mostly stock with the exception of a K&N intake system and a Y-pipe after the cat going straight back to a dual exhaust.

About 3 years ago two it started running terrible and threw a code "Misfire on cylinders 3 and 6"

I pulled the plugs and sure enough they were fouled. Replaced and all was well.

Fast forward to today, same situation. The truck starts running like garbage, then throws a code "Misfire in cylinder 2."

I am assuming I'll have to replace the plugs again, which is fine, but I was wondering if it had anything to do with my intake and exhaust.

Any help would be greatly appreciated. Thanks!

Joe

 

[doorgunner]

Beats me.......but I dump some injector cleaner in my gas tank every time I change the engine oil...it keeps the injectors from sticking open....

Were the fouled plugs sooty.........or were they oily?

 

[adsm08]

In addition to DG's question, did you only replace the affected plugs the last time, or did you do all of them?

Did you do wires as well? If not, I would do a full tune up, all 6 plugs, wires, coil pack, and fuel filter. The K&N setups are known to cause some problems, but it is usually lean codes, not misfires. I'll bet my left nut that your exhaust is not causing this either.