Another P1391 code post. cam sensor? dist? crank sensor?

[LockdUpXJ]

I have looked up many threads on cel P1391 but I can't find how to troubleshoot and diagnose what the actual problem is. I was driving home from work on i5 from Tacoma to federal way and going through fife the jeep stuttered and the rpms would spike way up under middle throttle then as I was getting to federal way it got worse and worse so I pulled Over and it stuttered even at idle and it died and through a code. I have a Bluetooth code reader in the jeep and it said it was P1391. Any thoughts as to where to start? I don't want to just throw money at replacing things that aren't the problem

[mtbxj87]

year and engine, trans? ill look it up

[mtbxj87]

if its 97+. p1391 intermittent loss of crank position or cam position signal.
Look at the connectors for both sensors, corrosion, broken wires, pulled terminals. then check grounds, voltage input and voltage output

[LockdUpXJ]

Its a 99 XJ 4.0. I'll check the connectors and go from there

[LockdUpXJ]

I checked the sensors at the end of the pigtails where they plug in, disconnected and reconnected them. Drove it and a few miles in the jeep started doing the same thing. Today I will pull the sensors and look at them clean them up perhaps. If that doesn't work I will have to start replacing the parts till it goes away

[LockdUpXJ]

I am starting to get frustrated..... yesterday i noticed the jeep was throwing coolant around the engine bay because the fan had worn a hole in the hose between the radiator and the coolant overflow so I replaced it, filled up coolant that it was a quart low on. today i turn it on and its idle is garbage and it now says check gauges.... the voltmeter isnt working..... it drives just fine (minus the idle) 10 miles to work on the interstate. ANY ideas?!?!?!?!

[LockdUpXJ]

HELP!!!!! does anyone have any ideas?

Update, I drove it again to lunch and the idle is such garbage it died a few times. the voltmeter is not working then worked... then didnt work after a few min (may be unrelated????)

[GordoSmasho]

Have you replaced the sensors. I would start with the cam sensor. Crank would shit off the motor due to spark loss. But just replacing both is good insurance. Just make sure and test the new sensors before install. They sometimes arrive bad.

[GordoSmasho]

Cam sensor testing
http://www.naxja.org/forum/showthrea...1003757&page=2

Crank sensor test
http://www.naxja.org/forum/showthread.php?t=1062496