HudsonN

It's a 4.0/AW4.

It seems to idle rough, and the second you start to rev it up it goes BUP BUP BUP BWAAAP (studders and then takes off).

When you're driving it, if you touch the gas pedal like an egg shell it goes okay, but pretty much dies on hills. If you mat the pedal, the exhaust starts to almost shake and then it'll backfire.

I checked fuel pressure, it's holding 50 pounds when running but the check valve is shot in the tank. Bleeds down pressure when you kill it. I disconnect the fuel line from the tank, and the rail, blew that out, blew out the fuel rail, swapped sensors on throttle body with known good ones and nothing.

Jeep was running fine about two weeks ago. He decided to wash the engine off with that degreaser stuff and it seemed to start acting up after that.

He said he cleaned some grounds off but that was about it. Here's a video of it. If you listen carefully you can hear it sounding really bad.

https://m.youtube.com/watch?v=rgDkw6ncTDM

It's throwing a code but I can't find my code reader. Obviously I need to get them read but any suggestions?

97grand4.0

If it bleeds off immediately when you shut off the engine, the filter/regulator needs replacing for sure. From experience replace the assembly or you just do it over in a month. A clogged filter will surely cause a stumble, it did on mine, I assume you have ruled out ignition issues?
I always say, when hunting a problem and you find something you're not sure of that is 'slapping you in the face' you have to fix that before you can say it that's the original problem.
The video sounds like you're missing a cylinder, .? You need to read the codes, can you do the key trick on the 98 xj?

HudsonN

Ignition issues?

No key trick on a 98, i just ordered a new code reader from amazon. I think i accidentally scraped mine in a jeep i scrapped about a week ago.

There seems to be plenty of fuel in the rail.

Maybe bad injectors? But then why would it smooth out?

CCKen

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