My truck hasn't been running right having an odd miss. I changed plugs and wires today, thinking that that was the problem. Indeed, it was part of the problem, but something else reared its ugly head. I took the truck out for a test spin and it ran ok for the first mile, and then things went downhill. The truck started to buck and miss worse then ever, eventually dying on me. I believe that the problem is fuel related since it has all the symptoms of running out of gas. I start it, it sputters and then dies. Pumping the throttle does nothing.
When I first turn the key on I can hear the fuel pump do its 2 second prime.
Upon starting it the truck lopes for a second or two and then dies.
I checked the pressure at the rail and only lost a 1/2 teaspoon or less before the pressure was gone.
Pump, filter, or other?

 

Replace the filter then test the fuel pressure with a gauge.

 

That's going to be my first step since for all I know the filter is origional. Also the cheapest part to replace. I'm waiting on the tow truck to show with my machine so I can start to check. Figures, I just put 12oz of seafoam in the tank and topped it up, hoping I simply had a bad tank of gas.

 

I like Bear Rivers idea to first replace the fuel filter, especially if you think it may be the OEM filter, as they are on a 30K scheduled maintenance replacement, so if it's OEM it's WAY past due for replacement!!!!

You can make loan of a proper fuel pressure test gauge, for a refundable deposit, at most autoparts stores "Loan-A-Tool" program.

Hopefully a clogged fuel filter is all it is & the fuel pump isn't damaged from having to work so hard to try & pump fuel through a clogged filter over a long time.

If it'll immediately start & run ok after the filter replacement, then you'll have the answer, but I'd still do the fuel pressure test Bear River suggested, to check the pump & fuel pressure regulators health.

Let us know what you find.

 

Thanks for the replies. Now I have 2 more questions to throw out...
#1 Where is the external filter located?
#2 Is there an internal one attached to the fuel pump inside the tank?

 

The filter is located under the drivers door on the inside of the frame. There's a removable bracket covering the filter. Be sure to disconnect the fuel pump relay/fuse (under the hood) and run until it dies. Crank it over a few more times to make sure the pressure is gone then disconnect the battery before disconnecting the filter. There's a special tool to release the lines from it.

As far as I know the only filter inside the tank is a screen type.

 

Even though depressurized the lines will still leak fuel when disconnected so be careful.

 

Thanks, the job is being done outside since I have so much 'stuff' in the garage that I can't even fit my quad in there anymore.

 

After disabling the fuel pump & running the engine to relieve fuel pressure, I also loosen the fuel tank cap to relieve & lessen pressure build up in the tank, before & while I remove the old filter.

Be sure to pay attention to the flow direction arrow on the filter when installing. The point of the arrow is toward the engine.

Remember to replace/retighten the gas cap & to re-enable the fuel pump when finished.

Let us know how it goes.

 

I too am a shade tree mechanic, but I don't have a garage, so don't feel like the lone stranger.

 

I installed the tank side of the fuel line to the new filter and turned the ignition switch on. I have pressure for the two second prime cycle and nothing afterwards. Is this to be expected or a sign that the pump has gone south? I haven't tried cranking it over as I can't depress the clutch, turn the engine over and watch the fuel all at the same time.

 

The two second pump run & cutoff is normal.

Now finish connecting the filter & see if it'll start & run.

 

Many thanks to all posters, between the tune up and the fuel filter my truck runs better now than it has for the 10 months that I've owned it. I didn't realise just how peppy the 4.0 is until a few minutes ago.
Of course when I tuned it up I found 2 plugs with cracked insulators, a rubber plug boot split and melting onto another plug, and one plug almost completely fouled with what I think is "Liquid Glass".
Problem solved...
Thanks again for your help folks.
Since I average close to 24mpg I wonder how many more I can coax out of the old truck now that it runs right.

 

Good feedback & to hear it's running better. Sounds like it needed some serious attention to past & present due scheduled maintenance.

Now that it's feeling all better, you'll be saving so much fuel that you'll have to watch closely to make sure the gas tank isn't running over!!!! lol