We just got back from a 700 mile trip to Oregon pulling a 23 ft trailer to go camping for a week in Grants Pass to see the fall colors and visit friends. Our 2002 Ex 6.8L 145K ran great, except for a glitch. At the first fuel stop it took 4 or 5 tries to get the engine started. Same thing after the 2nd fuel stop. The engine would chug, sputter and die, like it was not getting fuel, then finally start running. I didn't turn the engine off the rest of the drive and no other issues. The next day I tried starting it in the campground and it started right up. Tried several more times during the day, started every time. Went to the store one day, friends house the next day, no problems. Headed home after a week and stopped at a rest stop after 2 hours of driving. Turned it off and tried to restart it and it coughed/sputtered. I flipped a switch I had added for testing that connects the Inertia Switch directly to the battery, no difference still sputtered and wouldn't start. Turned the test switch off, let it sit for 20 min and it started right up. I didn't turn the engine off the rest of the trip and no problems, no surging pulling the trailer up steep hills or accelerating, ran great.
It seems while towing for periods of time and shutting off the pump it needs to cool down for 20 min or so before running again.
I drove it twice during the week we were camping without the trailer and had no problems.
Does the fuel pump "work harder" when pulling a trailer?
I'm thinking at 145K I probably need a new pump.

 

Best guess is your fuel pump is dieing or dead. You should be able to check fuel pressure on the fuel rail shrader valve. Gauges can be rented at your local auto parts store. Have someone turn key to on engine off and listen for it to prime.

I believe the tech folder has some write ups on fuel pump swaps if you plan on tackling this on your own.

 

Sounds like the old pump may be going away. I don't think it's the towing that is causing the weak pump to be an issue so much as the few hours of simply running (while towing) vs the shorter unloaded trips. At 145K you have done well, my factory pump gave up before 100K.

 

I carry a gauge, but didn't want to test it while in line at the gas station.
Once it started it was fine.
Thanks about the write up in the Tech Folder, knew I had seen that before, but didn't remember where.
The fuel gauge drops rapidly for the first 1/4 tank so it's probably time to replace the whole assembly.

 

Similar to what happened to me only mine started to sputter after we got off the highway and pulled into a diner parking lot. After it sputtered for a few minutes, it just died and would not start. While waiting for the tow truck for about an hour I tried it and it started, ran fine for the rest or the trip and then another 4 months until it finally failed.New file pump and it’s been great since. Only had 55 k on mine

 

On my Mustang when the fuel pump was suspected of being weak/intermittent, and not causing a shutdown but a significant loss of power i connected a fuel pressure gauge to the schrader, ran it under the back of the hood and proped it up under the windshield wiper so i could watch it while driving and sure enough about 45 minutes into my drive i stepped into the power, the engine shuttered and the fuel pressure tanked down to like 8 PSI and would slowly come back up to about 14, but if i stepped into the gas any more than maintaining my speed the pressure would fall, the pump was weak, and on its last leg, and only exhibiting the behavior after long drives. Doing the test that way allowed me to witness the pressure drops.

New Motorcraft pump solved the problem.

 

I've never had a fuel pump fail gradually and give that kind of warning. I agree that the high-mileage fuel pump is where I'd start, but I'm jealous of your getting these warnings!

The fuel pump failed on my 2000 Ex one morning as I was driving to work. Just 2 minutes from work there's a small hill and she struggled to get up the hill. I got her parked, shut off the engine, and she wouldn't restart. Fortunately, the fuel tank was only about 1/3 full and a friend helped me replaced the pump after work.

When the pump failed on my F150, I didn't even get that. Drove to the store, came back to the truck, and she said, "uh-uh. Not gonna happen.". The same friend helped me change it there....

 

Oh believe me, i wish it had failed instantly, the power loss drove me crazy trying to figure it out for a while, because it was so intermittent it was hard to track down.

I actually tested the fuel pressure twice before and it came out fine, but both of those times, it was on a cold motor, cold car, it was when i put the pressure gauge on and under the wiper and did some driving that i finally figured it out.

I was seeing all kinds of weirdness, even thought it was a tune issue, because it would ping occasionally when the pressure would drop, and i thought at first the engine was pulling power because of that, not due to fuel starvation.

Probably drove me nutts for 3 weeks, and wasted a bunch of my time trying to figure it out. Definitely would rather it have just poof dead, easy to track down replace and be done.

 

Got a new fuel pump installed and ready to put the tank back in.
Many thanks to Tom's procedure in the Tech Folder, huge help.
Hopefully that is our problem, we'll know in a week after our next trip.
The fuel level sender was not reading properly at the top end so it was probably getting there, too.
Also, what's with the OEM evap hose? The outer casing was flaking off and turned your hand black just grabbing it. It was soft so needed replacing. It is an 11.11mm (7/16") hose. Who uses/carries 7/16" hose? I replaced it with 3 ft of 1/2" fuel rated hose which works fine.
Our Ex is a CA emissions version so there is an additional Fuel Tank Pressure sensor in the plate, only difference I can tell from the 49 state version pump assembly.
Removing the old tank pressure sensor was a pain as I didn't want to break it while twisting it off the lock.
Not sure why, but from the Wiring Diagram it looks like the Fuel Tank Pressure sensor output goes to the rear Heated Oxygen Sensor (HO2S).
I was wondering what code would be set if the Fuel Tank Pressure sensor was bad, but it might be mixed in with the rear O2 sensor codes.

 

Update: Just got back from a 300 mile trip to Santa Cruz, gassed up twice each way and no starting issues. Looks like the new fuel pump fixed our problem.

 

That’s Great, glad you got it worked out

 

Thought so... Good work.

 

I had the same problem and changed the whole fuel pump and assembly. Mine is a CA version as well. For the tank pressure sensor, I discovered it's easier to remove and replace once the top assembly cover is mounted with the screw collar fastened. Then using a pair of channel locks with a rag over the sensor to give more leverage while pushing down.