Weekender

This is for a co worker but I have an F150 5.4 also so am familiar with the engine.

He says his runs fine in town and on the highway but after about 20 minutes the idle drops, gets rough, then the engine stalls. Just about in time to get to work.

He bought the truck with 75,000 miles, has about 150,000 now and has never changed the plugs. His cam phasors or timing chains make more fluttering noise than mine at idle and he's been told the phasors are bad.

I told him to change his plugs, coil packs and check to see if the FPDM is rotting away.

Any further ideas before he spends $1,500 on the phasor/chain/tensioner surgery? I've lent him my Lisle tool and his son, a heavy equipment mechanic, is going to help him change plugs. He needs a break. Finances are tight due to illness in the family.

Thanks,

Weekender.

'07 F150 FX2 SCAB, 133,000 miles.

pbhv

I had the same issues. Changed plugs, cops, phasers, chains and vct solenoids. It was still doing it up until I changed the oil to 5w40 Rotella t6.

I must have a low oil pressure problem at hot idle somewhere. It would do it with 5w20 and 5w30. Always used motorcraft filters.

Been running without any issues for months now...so if money is tight this may be worth a shot to tide him over until he can track down the real issue.

Weekender

Thanks. Sounds like the tensioner gaskets may be gone? Losing oil pressure in the tensioners. Going to a heavier oil may have bought some time.

Just speculating.

Appreciate the suggestion.

Weekender.

grss429

do not go to a heavier oil, like 15-40 our motors aren't meant to run that stuff. do you have any cold start rattles? get a oil pressure test done