When giving my 98 zj gas it just falls on its face. Driving I can't get it over 10mph. No check engine light has popped up. when I give it gas at the throttle body I can hear a backfire like noise through the air intake the engine won't even rev up. I would just run the codes but with out any indicator lights going off I don't know what good it would do. My wife is hateing on my jeep right now as I have her car and need to figure it out tonight to avoid a trip to the shop $$$.

 

Bump

 

Does it idle ok, no misfire......sounds like a fuel delivery problem though

 

It has been starting hard. Not cranking hard just having to do multiple light cranks to get it going. Idles ok once it get going, rough though aftershe the startoffice with real low rpm for a min.

 

And just now it starts up and runs fine...electrical maybe? I'm going to check the big 3 grounds, But any other ideas?

 

Fuel pump and filter is what it sounds like, check the fuel pressure before throwing parts at it.

 

The fuel pump and filter have been one of those things I have been dreading for a while. I just don't want to drop the tank to get at them, and my chilton's has been misplaced.

As it turns out the ground cable (2/0 welding wire) pulled the nut almost all the way through on my high quality wallmart marine battery connector/splitter. I tapped it back in and sodered it in place till I can buy an new one. It seems to have fixed the problem.

Thanks for the help.