Hey all....yesterday was a bad day for my 4.0 97 xj. I got gas on my lunchbreak then ran to McDonald's. When trying to leave my xj wouldnt start. It spat and sputtered and hesitated for about 20 seconds then died. After that nothing...it would just crank but no start. Came back after work and it started up. But anything other than light pressure on the gas pedal and it would hesitate and sputter terrible. Drove home and check fuel pressure. It checked at 45psi. Got my code scanner. Its not throwing any codes. I thought maybe I got bad gas. I put a bottle of heet in the tank then went and drove around. It definitely seems like the heet helped. It will start and drive now ok unless I hit the gas pedal hard. Then it pops and hesitates badly. Or if I slowly bring the engine up to about 3000 rpm and hold it I get the same result. Plugs, wires, cap, rotor, coil, crank position sensor, downstream O2 are all less than 4 months old. And my fuel psi is in the correct range. Any help? Kinda stumped with this one.

 

I'd change the fuel filter to make sure any junk didn't clog it up. You have good pressure so sounds like the filter may be ok. Does the fuel pressure drop when you put the engine revs up?

 

Pressure is good at raised rpm's. My xj dosent have a fuel filter. It has a strainer but its part of the whole fuel pump assembly. Read another post on here. Guy had similar issues as myself..someone recommended changing the O2. It was also mentioned to me at oriellys yesterday possibly it may be an ignition advance sensor ( cam position sensor). I dont have a lot of cash to throw at it. I just dropped most of what I had on a lift kit.

 

It doesn't have a fuel filter because you removed it? As far as I know, you would have a fuel filter along the side rails as well as the fuel strainer on the pump.


Have you tried the TPS tests on Cruizer's posts? I had a similar issue with the backfiring but it was a bad fuel pump that would be fine one day and then sporadic the next -usually when getting on the highway! Also, had cylinder #1 with an exhaust valve that wouldn't open because the rod had come out from underneath the rocker arm.

 

Thanks for the info. There is no filter in my fuel system. Maybe the previous owner took it out. Ill check the tps. I hope its nothing too expensive.