Hey Guys:

Already posted this at F150world.com, so sorry if you're reading it twice:

The unthinkable happened this weekend, my truck died and left me on the side of the road in NC. It acted like this: Severe 'bucking' when I was on the gas, no matter what gear. Felt kind of like it did one day when I ran out of gas. Only bucked when the clutch was engaged, idled fine coasted fine in gear with the clutch out. I pulled over, checked her up and down, couldn't find anything obvious, and re-started. It ran fine for another couple miles, then the problem came back, and worse. Pulled over and called AAA. Now it's at Tar Heel Towing and Service and I'm in VA...any advice on what it could be? I think it's the fuel pump, it has been whining for awhile now. Should I have the fuel pressure tested before I have any work done? Oh yeah, it's a '95, M50D with ~115K on it. Original everything save smog pump.

Any opinions/adivce are appreciated.

Thanks

Scott

 

I responded to your post at FTW-
But thought I would add that my front fuel pump died right at 115k

I used it 90% of the time rather then using the rear pump.

 

Thanks for the info....here's an update:

Mechanic in NC couldn't find anything wrong with it. Like I mentioned in the story, this problem goes away after the truck sits for awhile. Could it be the fuel pump relay?? Any info on how to check this out? Also, do fuel pump failures sometimes manifest themselves only after the pump warms up?

Thanks

Scott

 

Ah, you said the magic words "it goes away".

When if ever have you changed the fuel filter??? The problem you are describing is indicative of a clogged fuel filter. I had it happen on one of my mustangs, exact same symptoms. Replaced the filter, ran great again. What happens is built up sediment (crap) in the filter gets stirred up during operation and accumulates on the paper element at the exit of the filter. Flow gets restricted and it starts to sputter and won't accelerate, it might even die, but it will start and idle. My money's on the filter being clogged bigger than moose poop.

 

I vote with fastpony on the filter

 

Fast Pony:

That though had occured to me, as well. I last changed the fuel filter about 1.5 years (~20K miles) ago. The reason I did not suspect it here was a combination of the severity of my 'bucking,' the fact that 20K on a fuel filter isn't that much (so I was told, anyhow), and the sudden onset of the problem. I hope I didn't pick up a tank of super-dirty gas.

Anyways, since you had the exact same symptoms, and it's quick-and-easy, I'll have the filter changed (so sad to have my truck hurting and 2.5h away at some shop) and have the fuel pressure tested.

Thanks

Scott

 

I'll bet it doesn't have anything to do with the fuel pump or filter. I'll bet it has something to do with either the speed sensor, the RABS, or the PSOM.

Have the tech check for codes, and look for a 452.

 

stf8b I'm having the same exact problem you are,mine is an 85,i have replaced the fuel pump in the front tank the one on the frame,filter, ing.module, coil, mag. pick up, throttle postion sensor,reset the fuel relay! Man i'm about ready to pull what's left of my hair out! It's a 5.0 fi By the way HELLO everyone!!!

 

BTT!

 

Green Meanie 85:

Doesn't look the same as your problem, because a new fuel filter did the trick. Thanks, Fast Pony, you were right on. $35 for towing, parts and labor--if anybody is in the area of Reidsville, NC, and needs emergency service, give Tarheel Towing and Repair your business.

Thanks again

scott

 

Hey, glad I could help.

Good thing it was a "cheap fix", I know that feeling of impending doom....$$$$

That's the great thing about this group, out of all our responses, somebody always has the answer, different hero everyday.

 

stf8b i glad you got yours running, i got disgusted with mine for a while, and went and got a 91 bronco 351 to run!!

 

I'm with the guys who think it's the fuel filter. Although you might be onto something with the relay.

I can't imagine why the RABS or speed sensors would have anything to do with bucking. Why would the ABS system have anything to do with fuel?

 

Because that's how the ECM knows how fast the vehicle is going, and it adjusts the fuel and timing accordingly. It's a very common problem, and the complaint is virtually identical to this one.

Take care,
~Chris

 

Do you guys think my problem may be the same? Cold starts are fine but My '96 F150 4.9L 5sp w/53,000 cranks but does not want to start! It runs great other than that. HELP, please!!!