Originally Posted by 90renixxj

1990 jeep cherokee
has an 87 4.0L AW4
3 inch lift 33 Inch tires
dual exhaust from cat back no mufflers just the cat

First what its doing-

2-3 second cranking times (I know somewhat normal)

Very light acceleration itll drive fine

Pedal 1/3 of the way itll fall on its face spitting and sputtering like a misfire and backfiring until I let my foot off the throttle or floor it and itll even out once I get to speed and itll cruise unless I lift my foot a little and itll do it again.

It doesnt matter if shes completly warmed up or cold does the same thing no matter what. Only difference I can tell is if I drive it somewere say ten minutes and I shut it off come back ten minutes later it cranks over a lot longer than when she hasnt been run and it might kinda chug for a couple seconds and even out

What ive done-

Cps
Tps
Refreshened all geounds
(0 ohms at tps ground)
4 gauge cable ground rear head
Sparkplugs
Coil
Fuel filter
Fuel pressure 31 psi 39 with vac off
Cap and rotor
Cleaned egr valve
Light seafoam treatment through TB (crank times went from 5-7 seconds to 2-3 now)


Would an o2 sensor cause all this? I dont know how to test this?

Dirty or leaking fuel Injectors? I suppose I could take em out and check em?

What do yall think?