I have a 1998 jeep Cherokee 4.0 that I am having some problems with. I was having this problem before I had to install a new engine. When I take off it has low power and then will rev up and sometimes I will hear a knock from the engine, at times it will idle fine then just rev up. Before I had the engine replaced I installed new plugs, wires, cap, rotor, the cat is new with O2 sensor. If you have any ideas that would be great I have messing with this for awhile now.

 

What's the fuel pressure in psi? Firing order correct?

 

I do know the firing order is correct, but have not checked the fuel pressure. I did install a new fuel pump about 7,000 miles ago.