My hubby replaced the engine on my 2000 Jeep grand cherokee 4.0 inline 6 in January...(I am the reason it had to be replaced, run hot, busted head...thats a different story). The jeep has ran great up until last week, with 1200 miles on the new motor, ck engine lite on, showing code p1391. Going down the road, it starts sputtering and stalling with no warning. Sometimes it completely dies, but, always starts bk up, sometimes it just starts running fine again. I took to autoparts store, got the code, called the hubby (who is working very long hours and does NOT want to deal with the jeep problem). He changed the crank shaft sensor but not he cam shaft sensor. I had the same problem with the old engine... I have read all about this code p1391...I need to know what to check, change or sync first. Any advice is greatly appreciated because I am so very frustrated with this!!!!! I absolutely love my Jeep, but its got to keep me going running my kids, I have no time to be stuck on the road!!!

 

I would replace the cam sensor judging by what you described.

 

Agree with the above post, and if the crank censor is new, that'd be the nest in line. It's easy to change too.

 

thank you so very much...I will let you guys know after the cam sensor is replaced...fingers crossed this takes care of my problem

 

I've been having the same exact problem with my 1998 GC, I changed both cam & crank sensors, I changed the fuel pump yesterday and its still acting up! Please help

 

It's always creating some different problems as you told you are facing the problem with crank sensor and with engine problem. In my opinion we cannot fix it up because I had the same problem before I made all the necessary changes, but after some days again showing new problem .. I really fed up.. i need to bring to specialize car care shop....

 

Have you brought it to a national brand auto parts store, such as autozone? They can log into the computer under the dash, and see if you have a diagnostic code. 99% of the time its a free service. Is just hate to see you spend more money than necessary on what mabie a simple fix.

 

The original poster stated they had a P1391 code, so they are aware of a code being present.

 

alrighty gentlemen...replaced crank and cam sensors...reset ck engine lite......still sputtering and bucking and I am soooo beyond frustrated now. As i said before code is p1391. Here is a question for yall, Does the jeep grand cherokee have a "main" computer? I know i could google but i am looking for answers so i can go to bed..lol...new motor, plugs, plug wires, oil pump, water pump, radiator, crank and cam sensors. and i m not sure what all else is new...could there be a loose connection while driving? I know duct tape can fix almost everything and electrical tape can fix what duct tape cant...any and all suggestions are appreciated.

 

This is a statement you need to be extremely cautious with. A DTC means that there is an emissions failure caused by one of the vehicle's electrical components that is either an input or an output. A bad PCM or a grounded wire can be the cause of just as many DTC's as a bad sensor, injector, etc.

The ECM is the main vehicle computer. The best way of doing this is having a scan tool that can show data. Readings out of spec on the ECTS, TP, MAF/MAP, etc. can cause similar driveability issues as a cam or crank sensor.

 

I totally agree with jake92. There are many sensors that feed into the computer to make the jeep run right. Any one or more of these sensors malfunctioning, or faulty wiring of the connections, or the computer itself will make it run badly. The cheap code scanners from Autozone and the like are too simple to get the big picture of what is going on. A well trained and experienced service tech can tell the difference between a malfunctioning sensor and a computer that is malfunctioning.

I recommend using a qualified professional to get this under control. As you have found, you can flail around for days and not hit the mark. I know because I have done it. Sometimes, you just have to pay the piper. I'm currently shopping for a 1972 or older chevy truck so when it breaks down, I don't have to ask for help. 100% computer free.

 

can this be related to distributor, cap and rotor, wires or coil somehow?