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sebastian manrique
sebastian manrique, Auto Mechanic
Category: Car
Satisfied Customers: 2966
Experience:  Director Ejecutivo at Multiservicios Cruz de las Mercedes
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I get the code P1391. I had replaced the cam and crank

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Hi, I get the code P1391. I had replaced the cam and crank sensor. The light stayed off and the jerking stopped. I drove the car home and turned it off. 2 hours later. I went out to start it to go some where The check engine light came back on and the car was jerking again. Although its not as bad as it was. I took it back to the mechanic. He checked the code for the engine light. It is the same as it originally was the P1931. I am a current member and I think it was John who helped. I have a 2004 Jeep Grand Cherokee 4.7

Hello, I am Jose Sebastian. Your automotive expert, It's a pleasure to me to attend your question. Thank you very much for trust in just answer.

Dear customer, I would like to know the mileage of your grand cherokee and know when was the last time you replaced the timing kit?

Customer: replied 9 days ago.
152,000. It's never been replaced that I know of

Dear customer, what happens is that the error code that you are presenting is related to the timing of the crankshaft position sensor and precisely the symptoms that they present are related to this, I could tell you that the problem is the sensor and that it must be replaced but as Your model already has more than 150,000 km and the distribution kit has never been replaced at least every 120.000 the replacement shall be done, therefore you have to do it, anyway I recommend you to check the sensor connections and if you want to replace the sensor since it is cheaper than the distribution kit do it, but if the problem persists you will surely have to replace the timing kit.

Customer: replied 9 days ago.
Does the chain and gears both need to be changed

I recommend replacing it but there are technicians who do not, in reality a chain is very difficult to break, normally it can be a failure in a link to damage a chain but this is very difficult, and what happens with the gears is that the wear of the chain has to be the same as that of the gear because if you put new gears with the used chain they will create noise, then this depends on the technician. I repeat, I personally rather replace the entire kit.

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