Most definitely can be a fuel filter problem.

It also could be a fuel pump supply voltage problem. If the fuel pump isn't getting the voltage supply that it requires, it may be sluggish to react to demand.

 

Ill look into that, but how easy is it to drop the tank and check the connections? Its wierd, when the truck is running normal the heater is fine, but when it is lacking power the heater is just blowing normal temp air. Hmmm, anything on that situation?

 

Could be that the truck isn't burning enough fuel to heat up a large amount... Try changing the fuel filter if it hasn't been done, then if that doesn't help... you're going to have to check the fuel pump.

But first, the fuel filter, that's usually the cause of hesitation when ya stomp on the pedal...

 

Sounds like a plan, I was at the drive though today and I noticed a humming noise, sounded like an airplane. Anyways, it never turned off, just kept humming..It sounded pretty neat, but odd.

 

I had the same problem with my truck before. Ended up going through all the tune up ~motions~. The problem ended up being an out of toleranceMAF, and a failing fuel pump...but didn't get a code forthe MAFuntil it got "bad enough".

Changing the MAF got me back to about 75% health...the fuel pump got me the rest of the way.

Icarus

 

Ok, so friday I am getting the radiator flushed and the heater core flushed, then getting the thermostat and fuel filter changed. I will see if that fixes the problem, but I doubt it since I hear the humming\whinning noise the whole time. Unfortunantly, it might be the pump. Fingers crossed..

 

The humming/whirring noise is the fuel pump working. For your '01 extreme your pressure should be closer to 60psi at the "shrader valve". I have seen a thread here where someone put the fuel pressure gauge on the valve and had it in plain site after closing the hood and took a drive and found out that the pump would occassionally drop under the minimum needed for the truck...when they replaced the pump the problem went away...

 

Id say check the CAT im goin through the same issue now...either the 02 sensor or CAT im guessin

 

Do you have an oiled,aftermarket airfilter? Over-oiling will cause havac with the maf sensor, which in turn will affect the transmission line pressure.

 

nope, brand new O2 sensor, and high flow cat with exhaust, and I thought that the fuel pump went off after a few seconds?? Mine stays on the whole time.