I have a 5.4 ltr Triton with 61,000 miles. My wife noticed a month ago, some hesitation in the engine on the road. I took it for a test ride, without finding anything wrong. A week ago she said it was getting really bad. So we went for another ride. I noticed it this time, but didn't think it was really that bad.
So, I decided it might be fuel/air mixture or delivery. I changed out the aircleaner and fuel filter. We took it for a ride and it seemed to have fixed the problem. My wife has an hours drive to and from work, so everyday, I'd ask her how the van was doing. She said no problems what-so-ever.

Until yesterday...... We were on our way out to our cabin in the hill country of east Texas. We filled up on our way out. As we got into the hills, we noticed the van was herky jerky again. The van seemed to hesitate all the way out there. It never seems to want to stall or misidle, just Skips a beat or two at all speeds. It runs smooth at idle and doesn't seem to have any misidle at all.

I took the cowling off and took it for a ride without it on. I didn't notice any odd noises eminating from the engine compartment. I did notice a soft vacuum sucking sound, nothing that would make me believe I had vacuum leaks. I figured that was normal considering. I also noticed 2 soft clicks from the transmission as I let off the gas to come to a stop, but that was after a strong, steady excelleration. I was thinking that was some sort a valve inside the tranny to kick it into lower gears. Not worried. Just some FYI.

Has anyone experienced any problem with herky jerky out of the van without stalling? I've tried looking into f150's and the rest that might have the 5.4 Triton. I have yet to see anything closley resembling my problem.

Could I have a vapor lock problem? Could there be something else wrong with ignition? I haven't taken it to have the codes read yet, but will. Is there more than the 2 fuel filters I know of? (tank and frame rail-next to tank) Is there one closer to the fuel rail in the engine compartment? I can't find a book on it so I don't know. There aren't any dummy lights on either.
If someoone could help me out-it would greatly be appreciated.

 

sounds more like an ignition issue... You say it's got 60kish miles on it.. I'd go ahead and replace the plugs.

 

I could have sworn that these newer engines had garanteed 150,000 miles plugs? I've read the book and it doesn't say anything about changing plugs at 30 or 60,000 miles. I know your suppose to change them at 25-30,000 on the older model engines.

I was thinking yesterday about junk/water in my gas. I'm going to try some "drygas" solution today and see if that helps any.

If that doesn't work, I'll take a look at those plugs. Thanks for your help and reply.

 

It may have the 100k mile plugs in it, however if it gets alot of extended driving time it may need them sooner.

 

i had a similar problem with my '97. turned out to be a bad COP.

 

OK, you got me, what is an COP?

 

Coil on Plug. No spark plug wires, each plug has a coil sitting on top of it. They go bad fairly often, will cause a missing or hesitation on accelaration. Mine was most noticeable when trying to maintain speed going up a hill.

 

The same with me on my 99 E150 with the 5.4L. Just recently I got the herky jerky thing on acceleration and the dealer diagnosed it as a bad COP. It is fine now.