4.6L Could be bad!!!
 

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Ok, I have a 2002 Supercrew with a 4.6L 138,000 miles- Driving home to day with the AC on I went to pass a car, put the hammer down, and instantly I knew something was wrong. As I was passing the truck kicked down, rpms went up like normal but then I lost power. I kept losing power until I actually had to pull over. The truck wanted to idle at 4-500 rpms and barely kept running. I only had a couple miles to my house so I limped her home. The only way I could get any RPMs out of it is by pumping the pedal then it would gain some RPMs to get some speed then I would coast again until I could get it to kick back in. Once I got home I let the truck idle and it died. It still starts but it runs (barely) then dies. Im a little confused, and nervous. I have had 4 coils already replaced but this seems different than those times. The check engine light never came on- Anyone have any ideas? I wish it was a fuel filter, but I doubt it, just hope it isnt in the timing. Any help would be REALLY appreciated, Im suppose to be leaving Tuesday to go Antelope hunting and I need by truck!
Thanks!

Mechanical failures are usually catastrophic so I doubt you have done anything bad to the engine. That leaves electrical and fuel. My guess is fuel. You are going to have to check fuel pressure. Could be a bad fuel pump but just no way to know except to check the pressure.
Hope you figure it out.

Good luck.

Well Im hoping its as simple as fuel, I was just suprised that my problems came exactly when I was passing. Seems just a little odd!

I'm just guessing here but was the truck running hot? It might have gone into "limp" mode where it runs on only 4 cylinders and just barely gets you home.
Edited: Just remembered, the cat might have plugged up??

limp mode???

sounds like an erectile dysfunction...

sounds like a fuel problem to me replace the fuel filter and check fuel pump voltage and fuel pressure. just hope u didnt get sand in your fuel. when was last time u filled up?

I filled up yesterday and put on around 70 miles with the new gas before I started to have problems.

Just replaced the fuel filter, no help!!! Need to get the pump tested I think.

sounds like bad gas.. u will need to clean the fuel lines, rail, injectors and probably replace the fuel pump...

if u want to find out if its a fuel problem take a can of B12 or any type of carb cleaner or throttle body cleaner unplug the fuel lines or tap the fuel pump to get it to shut itself off or just un plug the fuse... but have someone push the pedal so the throttle body is partially open and have them crank on it and while they are cranking spray the B12 into the throttle body and it will burn in the engine. and that will tell u if u have a fuel problem. the engine will run and will actually clean the engine out fairly well:-p.

Well this gets interesting, so I checked fuel pressure, 40 lbs on the nose, so then I sprayed some carb cleaner in the intake to see if it helped, nothing. Then I started to think well maybe its the converters and they are plugged, so I took each of the O2 sensors off to see if that helped, again nothing. So I pretty much got mad and took the intake hose off where it reached the air filter started the truck, again nothing, after I shut it off I happened to look inside the hose and seen a little piece of leaf ( 1/4 inch by 1/4 inch) on the sensor. I plucked it out with tweezers, and then figured I would start the truck just to see, and sure enough, running like a champ. I was and still am absolutely stunned (yet happy). The leaf must have caused the sensor to act up but wasnt enough to completely shut the truck down. Strangest damn thing I have ever seen. 4 hours of searching eliminated in 2 seconds, unbelievable, but hey thanks guys for all the help, I really appreciate it!

bvwarrior,
Glad it turned out to be something simple.
The only sensor you can see from the filter side would be the MAF. It senses how much air is entering and adds fuel accordingly. No air was getting past so it was essentially telling the engine you were idling; so it was a low fuel problem, just not caused by the fuel system.
My concern now would be how did a leaf get past the air filter. You should do some investigating because if other things of that size are getting in you can really damage the engine.