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Engine low on power


NAXJA Forum User
Hello all,
I bought a 95 Cherokee 4.0 auto.
Engine was fresh and just had the head rebuilt but not installed when I got it. assembled it and it would start and die within a few seconds, after a bit of research I ended up unplugging the tps and it stayed running so I installed a new one. started fine took it for a drive and all seemed well until it went to shift 2-3, it just hung at like 4200 rpm, I let off the throttle a bit and it shifted but wouldn't accelerate much more. It felt like it wasn't advancing timing or it was pulling timing, so I stated swapping sensors including:
cam angle sensor in the distributor
coolant temp in the t-stat housing
fuel pressure regulator
and finally crank position sensor.
have tested the fuel pressure and flow. will flow over 1 gpm, and will get to 90 psi.
Still no power up top. so I thought maybe it had to do with tire size (32") so installed a ford 8.8 with 4.10's and regeared the front. not really any change.
could I have screwed up the cam timing? (idles and accelerates smooth) or could the pcm be bad?
Forgot to mention I do not have a cat, and I rounded up a scanner and where im noticing problems it's advancing the timing 30+ degrees
Sounds like you've shotgunned all the sensors. If you have a meter, I would verify at least the TPS is good as chinese parts can be bad out of the box. I would also verify the distributor isn't a tooth off. Check the throttle body to trans cable adjustment, as that can cause failure to upshift as well.
TPS says just under 4 volts at wot. Distributor is correct, had to spin the gear on the distributor to get it all to line up correctly though.(absolutely no change in drivability) And have reset the tv cable a few times.
Fuel filter? Fresh gas? Still could be tps.

I replaced the tps a second time thinking i may have cheaped out the first time. Fresh fuel yes. I didn’t change the fuel filter yet because the fuel system test seemed good, but I planned on getting one.
Just because you have good pressure at idle doesn't mean it's not restricted at wot. Definitely change the filter, probably something else going on here too though. BTW, I've had 3 bad tps's in a row out of the boxes :/