Hi all! I've just bought my first cherokee today (1996 4.0 aw4(?) np242), and now i need some advices)

First of all, there is some strange thing with acceleration. Sometimes (like 3 times per hour) gas pedal goes soft, engine starts shaking softly, and car loses speed. If i plug neutral and overgas, or just turn engine off, problem disappears for some time. Once i heard bang from muffler at that time. What could it be?
Second thing is that i can't find "power mode" button for my aw4, so may be it's not aw4?

P.S. There is no errors in computer. Check Engine blinks 5 5.

 

I believe 90 and up they got rid of the power/comfort switch. I might be wrong on it starting in 90 but your 96 definitely won't have it.

 

Yeah, You are right about them getting rid of it. But, like you I don't recall what year the did away with it.

 

Thank you, looks like you are right. But the first problem still makes me nervous.
The best thing i found about it is the gas pump owerheating, and looks like i have very-very strange pump there - taken from some other russian (may be even soviet 0_o) car. I'll try to replace it and see what happens next.

 

Just curious, How do you know that the fuel pump is over heating since it's in the fuel tank?

 

I've just done some internet-research with my sympthomes) I'm still intrested in other possible versions.

 

If you think that you have a fuel problem you need to verify your fuel pressure at the fuel rail. I don't remember if the 96 suppose to be 39psi or if it's 49 psi.

 

Don't forget to change the fuel filter!

Any intermittent problem like that to me suggest wiring problems. You might crawl under the Jeep and inspect the wires from the fuel pump.

One sensor that can cause this type of problem is the Manifold Absolute Pressure sensor. It's the small box on the firewall just above the engine. The vacuum hose from it must be in peak condition, any cracks (which are common from vibration) will throw off how much fuel the computer uses.

A pressure test at the fuel rail would be a good idea too.