Ok so Ive got a new problem with my jeep. Its not really bogging, its more of a loss of power at WOT. The engine wont go above 3000RPM even with the peddle floored. I used to be able to floor it and it would almost redline and run beautifully. I also want to note that in park and neutral it revs up just fine.

Some background info:
Year: 1990
Engine: 4.0
Trans: AW4 4WD with NP231

Things checked and already ruled out.
-fuel pump
-pressure regulator
-fuel filter
-sparkplugs, cap, rotor and plugs
-tps
-cps

I also want to note the jeep was running perfectly fine before I tore up my yoke and dropped the driveshaft going down the highway. I replaced the yoke and the driveshaft and now my jeep has a major loss of power. It also only does this while in gear. In neutral or park I can rev it as high as I want and it sounds fine. Any thoughts?

 

Did you knock an o2 sensor out?

What DS went? Front or rear?

 

Check to see if any fault code stored in the ECU.
Turn ignition to ON -- OFF -- ON --OFF then ON and counting the CHECK ENGINE light, watch for the pause between.

 

x2 on o2's

speaking of DS's... watched a jeep go by the other day with the front hangin down... sketchy cause it was bouncin around a lot.. at least it was connected at the diff., not the TC...

 

That should and could have easily been removed.

 

i know, right!! its a head scratcher... then again, the last time i was under there pullin the front DS i managed to strip ONE of the 8 bolt heads, making the job futile... maybe he ran into the same issue? idk, ive seen the jeep around before and i know the people are pretty red... lol, but whos not around here, at least to some deree...

... i mean redneck, not ginger... haha...

 

Codes. You need them read.

 

Fuel pressure. Need to check it.

 

See if the cat is glowing, maybe ds hit cat and broke materal uo, but I like the fuel idea to, maybe it bent a fuel line.

 

Its a 1990 renix, that means it doesnt store codes. Also the rear yoke is the one that blew up and dropped the rear shaft. I cut the engine as soon as I heard it snap and was going maybe 15mph. I cut it off before it did any damage. The jeep underside visually has no damage I can see. Not a scratch actually and I believe the driveshaft just hit the ground pretty much. All the sensors are still connected also. I have a feeling my fuel pump I just recently replaced is garbage.

 

DS is prolly just a coincidence.

 

You were going 15mph on the highway?

 

hahaha! he might of meant the sidewalk??? lol but drive shaft sounds like it has nothing to do with power loss...

 

Finally found out the problem with the jeep. It turned out to be a bad fuel pump that I had received. Returned it and got an OEM one. Now it runs fine. The driveshaft was just a coincidence. BTW I was on the merge lane on the highway and had just pulled out of a shopping center. So yes I was going 15mph on the highway when it tore off. Note to anyone else ever doing a fuel pump swap NEVER USE THE AIRTECH **** PUMPS!!! You will save yourself soo much trouble. I went through 3 with the parts store and finally was fed up and got a bosche one.

 

Am I the only person in the world that got a good Airtec?? I wo.t buy that brand again from what everyone's feedback is but Jeeeze I feel lucky.