03 XLS 4.0 will not increase RPM

[2Fish]

My 03 XLS 4.0 4x4 167k will not accelerate. No codes in memory. It will start normally and idle, when I depress the accelerator (in neutral or gear) it tries to increase RPM but will not, just sputters a little. When I let off the accelerator it lopes for a few seconds then idles normally. It almost acts like it's not getting enough fuel or air.

I'm thinking low fuel pressure, maybe the pump but do not want to just throw parts at it. Anyone have any suggestions or know what normal fuel pressure for this vehicle should be?

Thank you in advance for your reply.

 

[swetrid]

I would say pump or cats are clogged.

 

[2Fish]

This morning I started it and it ran normally for less than 30 seconds then back to the same. I shut it off and now it is a no start condition. Still no codes, my scanner is an inexpensive engine off reader from Autozone.

I agree pump or cats at this point. Fortunately the cats are bolt up so I will open the exhaust tonight and check fuel pressure, the go from there. Do you happen to know the correct fuel pressure for the 4.0 (K)?

Thanks again.

 

[hobbitak]

sounds alot like a fuel filter as well....if you find that the pressure is down check filter.

 

[03 Explorer XLT]

The Haynes manual says 28 to 45 psi.