lack of power - fuel pump going bad?

[Corn98632]

I am stumped.

I have an 05 explorer xlt, 4.0 SOHC V6 with 191K miles.
With about 8K in repairs

In the past 6 months I have replaced, the front wheel hub assemblies, rear tie rods, upper and lower ball joints, TRANSMISSION, replaced the fuel filter, oil change/air filter, had the throttle body cleaned, had the idle control system reset, ran some seafoam engine cleaner through the gas tank, replaced the catalytic converter, all 4 o2 sensors, new spark plugs and wires. I think that's it.

Rough idle at stop lights, doesn't bother me too much. The problem I'm having is that it's sluggish. It takes a good 10 seconds to get up to 35 from a stop. Going 65 on the freeway up a hill, and it just feels like it doesnt have the power and doesnt want to go. Going up a hill the other day in town went from 35 to 20 and didnt want to go, then it just surged and started hauling.

Have checked, no signs of a vacuum leak. Was thinking maybe intake manifold gaskets or PVC valve, but mechanic says no leaks that he could find.

please help!!

 

[imp]

I am stumped.

I have an 05 explorer xlt, 4.0 SOHC V6 with 191K miles.
With about 8K in repairs

In the past 6 months I have replaced, the front wheel hub assemblies, rear tie rods, upper and lower ball joints, TRANSMISSION, replaced the fuel filter, oil change/air filter, had the throttle body cleaned, had the idle control system reset, ran some seafoam engine cleaner through the gas tank, replaced the catalytic converter, all 4 o2 sensors, new spark plugs and wires. I think that's it.

Rough idle at stop lights, doesn't bother me too much. The problem I'm having is that it's sluggish. It takes a good 10 seconds to get up to 35 from a stop. Going 65 on the freeway up a hill, and it just feels like it doesnt have the power and doesnt want to go. Going up a hill the other day in town went from 35 to 20 and didnt want to go, then it just surged and started hauling.

Have checked, no signs of a vacuum leak. Was thinking maybe intake manifold gaskets or PVC valve, but mechanic says no leaks that he could find.

please help!!

@Corn98632
Sounds like possible insufficient fuel flow. '05 has returnless fuel system, varies fuel pump speed to maintain constant fuel pressure. These models use a Fuel Pressure and Temperature Sensor to command data to the PCM (computer). Usually, a fault generates a trouble code, and turns on the Service Engine Soon light. Is that light on? Need to check for codes before proceeding, which likely involve measuring the fuel pressure at the fuel rail. You may find that the pump is at fault. imp

 

[Mbrooks420]

What about the other cats?

 

[BrooklynBay]

Did you test the compression of each cylinder?

 

[imp]

What about the other cats?

@Mbrooks420
A good idea. Exhaust restriction will surely kill power; no flow = no go. Should throw codes, I'd think. imp

 

[Corn98632]

I had the entire cat thing replaced. There were three of them on there.

I don’t know what “checking at rail” means, I’ve seen it a lot. While the engine is running but idling my scanner says the fuel psi is about 32-35.

No check engine or lights are on.

Everyone that’s scanned it has said that it says something not being able to communicate with the computer or something not complete or something like that. But they haven’t given me the code. Someone said that it said the vins don’t match so that means that at some point in time someone has replaced it. The people at the tranny shop said that it would say that because there’s an internal checklist it needs to complete but that was 3,000 miles ago, it should have completed that by now.

I don’t know if anyone has checked the cylinders while in there.

 

[Mbrooks420]

Checking the fuel pressure at the rail is hooking a gauge up to the fuel path directly where the injectors are fed from. Mechanical fuel gauges are cheap, and hooking one up to the Schrader valve is easy.

 

[imp]

Checking the fuel pressure at the rail is hooking a gauge up to the fuel path directly where the injectors are fed from. Mechanical fuel gauges are cheap, and hooking one up to the Schrader valve is easy.

@Mbrooks420
It is exactly as you say, but I think the '05 4.0 has no Schrader valve. AFAIK, my '04 does not. Maybe ALL 3rd. gens. do not. Or before "returnless", maybe they did. At any rate, if no check-point is provided, opening up the fuel connection is necessary to hook up a gauge. imp