I've got a 97 E-350 witht he 5.4 triton engine 75k miles. As of recent it started running like crap. I've changed the plugs, fuel filter and no change. It's got a hesitation when at a cruising speed, then if you force it to downshift its ok.

I'm told the coil packs might be bad, how could I trouble shoot the bad one? And I'm interested in changing some of the old censors which maybe a problem just in case so which ones are recomended for replacement? I have no check engine light on so I'm not sure if a computer is gonna tell me anything.

thanks Mike

 

I would first inspect the pcv hose elbows for cracks. The one on the rear of the intake manifold is known to split over time and cause a vacuum leak. Also clean the MAF filaments with TB cleaner or brake parts cleaner. Just do not touch them.
It could be from a bit of a lean condition.
You could scan the computer for a stored code for a misfire. Itis hard to diagnose which coil it is until you get a code.
Did you put dielectric grease on the coil boots when you did the plugs? Were the boots still fairly soft and not brittle?

 

I will check those vaccum hoses and clean the maf. problems started before I did the plugs and it was no change after. thankyou for the advice I will let you know.

 

Good luck.

 

I cleaned the maf, the little hole with the thin wires inside with some carburator cleaner and the truck seems to be running better. I'm gonna try hitting it again witht he spray tomorrow. Thankyou for the advice, much appreciated.

 

Glad to help

 

my dad has a '98 f250 (the goofy 7 lug truck) 5.4L with the same exact problem. he has changed out about just about everything; wiring harness, plugs, coil packs,oxygen sensors, maf and intake sensors, EGR valve and sensor, crank and camshaft position sensors, injectors, even added an aftermarket exhaust (header to tail pipe) due to some exhaust leaks. we are running out of ideas there is probably more he has changed but thats what i can think of. using the ether trick we didn't find any vaccuum leaks either. so good luck to you, and if anybody can help please. i'm tired of having to loan him my truck.