misfire 4th gear, 65mph, full throttle

[lil'_big_truck]

Hey all,

I'm having trouble with a misfire with my ranger. I had posted about it earlier but I'm still struggling to diagnose it. here's when it typically happens:

accelerating to highway speed
4th gear (manual trans)
full throttle
sometimes after shifting to 5th and load decreases

engine begins to run rough and then shakes pretty badly and a flashing CEL appears. But once I ease off for a few seconds, the CEL goes away and the truck runs as normal. I've plugged in my code reader and there are no stored or pending codes.

motorcraft spark plugs put in Friday
NGK plug wires
new coil
have run seafoam through the gasoline
new fuel filter sitting on the bench (I loaned my truck to my parents for a bit)

Has anyone else experienced this? is there a known fix? Thanks for the info.

 

[Uncle Gump]

What you describe sure sounds like an ignition misfire. Does it still do the same thing after the ignition component changes?

 

[lil'_big_truck]

What you describe sure sounds like an ignition misfire. Does it still do the same thing after the ignition component changes?

No change at this time. As I'm searching, I'm starting to wonder if it's the cam position sensor? would that cause a similar issue? could I maybe change just the sensor or is it worth switching out the whole synchronizer?

 

[Uncle Gump]

Anything is possible I suppose. Being the problem is so specific... I kinda doubt that is the problem.

That said... the cam synchronizer is known to fail on the 3.0L engines. If it fails... you lose the oil pump then the engine follows. Depending on mileage it might be worth doing an inspection and replacing.

 

[lil'_big_truck]

Anything is possible I suppose. Being the problem is so specific... I kinda doubt that is the problem.

That said... the cam synchronizer is known to fail on the 3.0L engines. If it fails... you lose the oil pump then the engine follows. Depending on mileage it might be worth doing an inspection and replacing.

the motor has 104,000mi on it right now so I would hope it doesn't have a part failing like that at this point. My thought is that the problem is either that, fuel pump is clogged, or another unknown electrical sensor having issues.

 

[O No 3.0!]

It sounds like an ignition related problem. If it were fuel related it would be more of a bogging or just lack of power, and in extreme cases, lean backfire thru the intake. I would pull the spark plugs & look them over for signs of misfire or contamination of some kind, like oil or coolant. If you see nothing obvious, i would do a compression test & a fuel pressure test.

 

[Rearanger]

Codes, scan data?