wvblackjeep

hi new to to site i have a 1995 cherokee sport 4.0 auto 4x4 same issue.
thanks for the insight on the o2 censor. ive already did a fuel pressure test (ok) cap, rotor, plugs, fuel filter. If I drive like i stole it it runs fine but under 2000rpms it doesnt want to go. also had a new exaust put in. will let you know if o2 works

sgt_why

wvblackjeep - Maybe check the catalytic converter as well ... have replaced those on every Jeep I've owned now. (3 - all 1992 or 1993 models)

With a plugged cat, it would idle great - but choke and struggle when driving.

steve_k_37801

When I had my 92 I had the same issue. Mine ended up being spark plug fouled out. Sounds like you have covered that already. Good luck though.

96Cherokee113

Well, I do have a check engine light. It scraped off road and tore the wiring to shreds. It was around the same time I changed the muffler and added octane boost (maybe too much) so it's a little hard to tell why mine bogs exactly so much, but I'm sure it's the O2. I'm pretty positive the bucking is from the same problem. I'm getting new O2 sensors on Friday so I'll let everyone know how it goes.

sgt_why

96Cherokee113> Not having an O2 sensor at all --- would definitely cause issues.

The O2 sensor helped - I can still notice a loss of power < 3000 RPMs -- but its only a slight sluggishness ... and not total loss of fuel like it was before.

Feels like I'm getting 80% of the power now ... but still notice hesitation when under 3k rpms ... enough to cause me to have to downshift to get power back.

Steps taken so far;
:: replaced ignition coil, plug wires, cap & rotor and plugs w/ bigger gap (4.0L firepower kit)
http://www.quadratec.com/products/17610_60X_PG.htm
:: O2 sensor (recently)
:: Cat-back exhaust replacement
:: and 2008-2009 replaced (3x) Fuel Pumps till I got one that didn't flake out on me.

sgt_why

could it be bad gap on the plugs ? Think the docs for firepower said to use 0.65 ...

Neo101288

its the tps but thats my .02

wvblackjeep

my engine code came up as 27 referring to fuel delivery system o2 code did not show. have replaced cat converter and muffler within the last year.
checked each injector for proper ohms checked ok also checked wires to injectors tested ok . i dont know how to discribe exactly in words what is doing but will try. when driving at a constant speed say 50mph rpms steady at 1800 it will feel like the rear end lock up for a second jerks and releases
then when giving raising the rpm quickly or letting off gas drives fine. also this is not a constant issue some days it will run all day with no problem.

could the ignition coil cause this? I would think either a coil would work or not
it wouldn`t be intermittent. again thanks for your comments

wvblackjeep

also check tps ok

Neo101288

checking the coil packs would be a good idea my friends mustang did that when his coil packs started to go but they have there own code i would imagine but that will do the same thing as the tps or an injcetor

95yeti

this happened to me and i changed the coil pack and it has run fine

wvblackjeep

going to change ig coil .
also chased wiring to auto shutdown relay control circuit not getting the proper ohm reading to pcm book says to replace pcm. not going there yet.

al2ride

The hesitation on mine was caused by a clogged catalytic converter. I put a straight pipe with turbo muffler and she got all her power back and more...

ZachsXJ

I'd say that sounds like a bad pump, many ppl have had the same symptoms and those are exactly the same symptoms I had when my pump went bad. Make sure your pre-filter is clean also when you put the new pump back in b/c that can starve the pump and cause the same symptoms.

wvblackjeep

would a fuel pump run intermittent.