I recently purchased a 2003 F250 SuperDuty CrewCab pickup with 45K miles on it. The truck has a 5.4L with automatic transmission. The problem I have is that the truck appears to be very sluggish. When trying to accelerate to pass the truck will downshift and the RPMS will climb to 4200 and the engine will begin to detonated and the rpms will fall to 3800 and stay there as long as it is held. On a steep grade such as a bridge the truck will not reach above 60 miles an hour under these conditions. The local Ford dealer checked and found no error codes on the truck and speculates that it may be a fuel pump beginning to fail but they will not say for sure if changing the pump will stop the problem, they supposedly check the truck did admit that there seem to be a problem but was advised to drive it until the pump fails and then I would know for sure. Any suggestions on this problem would be greatly appreciated.

 

Fuel filter? Not like in the book, it's a service item!

 

I forgot to say in my post that I had changed the fuel filter but thank you for the suggestion.

 

A fuel pressure gage would tell you for sure, When I have a situation like this I tape a fuel pressure gage to the windshield and go for a test drive. The other thing to look at is when the problem is occurring, if you let off the gas some does the performance get better or worse?

 

Is the 5.4L stock? Any mods like oil air filter? Many times a condition like this could be a result of a dirty MAF sensor. If you remove it and clean it with electronic cleaner and replace...that could do it. OBTW: The dealer does not "service" the MAF sensor, they will only replace it. They feel it is a NON-serviceable part.

Good luck...

biz

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2003 F250 SD SC 142" XLT FX4 V10 Auto 4x4 3.73s

 

The engine is stock and I will check on the oil filter and I will check the MAF sensor, thanks for the information.

 

I will definitely take your advice and give it a try. Thanks

 

You might also want to pop out the air filter and give it a look, never know the original owner may never have changed it.

 

Thank you for the tip, I took the truck to another mechanic that I trust and he is going to go through it I hope that he may be able to help.

 

Another thing to check/have checked is the catalytic converter.

Couple years back, a friend asked a few people for help with his F-150. Under light to "normal" acceleration, it would get up & go just fine. But, when under "heavy" acceleration to wide-open-throttle, it was just bog down.

We spent the better part of two days doing a complete tune-up (plugs, cap, rotor, fuel filter, air filter, etc.), swapped out the fuel pump....nothing seemed to help.

Beings that we were doing all the work in the barracks parking lot...not having anything resembling a shop & adequate tools...we told him to drive up on a curb, in order to get a little more room to work underneath. On his first attempt to hop the curb, he got partway up, the truck died, and rolled back off of the curb. I happened to be standing towards the back, on the curb-side of the truck. And heard an odd rattling when it rolled back off of the curb.

After more investigation, blah blah blah....we found out that the guts of the catalytic converter were broken up. Not exactly sure what all was going on inside it, but pulling the exhaust off just in front of the cat resulted in all the power in the world, so to speak. He had a replacement dropped in pretty cheap, and it was as right as rain from that day on.


Long shot (being a newer truck & all), but I figured it was worth mentioning.

 

Appreciate the help and I have been considering opening up just before the converter to see what happens. I think I will definitely give it a try. Thanks again