I have a 2006 lariat f150 with the 5.4l 3V engine. The only mods are 6 inch lift and a flowmaster exhaust that came on the truck when I bought it. It has 85000 miles.

My question is this. What is causing it to ping or have pre-ignition? I just changed the spark plugs. Its had regular maint. Including replacing the fuel filter, and having the engine and fuel system flushed. I have replaced the MAF, seafoamed the engine, and even tried running premium fuel. Nothing is working.

From what I have read about it, its caused by the engine running lean or carbon deposits. Any ideas on what I should do next? There are no CELs or stored codes whatsoever. Thanks for your help in advance.

 

Long shot - but what about R&R'ing the front O2's they are likely done -especially if you used Seafoam - which can pecker them (don't ever use that crap again - it is NOT good or needed).

A Motorvac of a BG treatment at the dealers wil do a much better job on carbon deposits.

BTW - which plugs did you use?

Also - see if there are any PCM flash updates ...

Good luck.

MGD

 

I had it flushed at the dealer 1st. I honestly cant tell you off the top of my head what plugs were used.

Wouldnt a bad O2 sensor trip a CEL?

Also, there were no stickers under the hood indicating the PCM had been reflashed. Would that be something the dealership would have to check for?

 

mgd

 

Thanks for the tip. They hooked it up to this machine, ran some cleaner through the engine, then drained and changed the oil.

Would a vacuum leak cause this problem? I sometimes think i hear one, but can never find it when i get under the hood.