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brownjeff, ASE Certified Technician
Category: Jeep
Satisfied Customers: 13886
Experience:  17 years experience, ASE certified, dealership certified, Service Manager for 15 years,
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98 Jeep Grand Cherokee: Engine

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98 Jeep Grand Cherokee, 190k miles: Engine cuts off with no warning, and in all conditions, warm, nearly-cold, at idle or interstate speed. It can go for days with no issues, and then this morning it cut off twice in traffic. Usually re-starts, sometimes does not quickly re-start. Noticed gas mileage dropping lately, from avg 18 to avg 13. Recently replaced plugs, old ones did not look "bad", but noticeable increase in pep w/new plugs. No dash lights, all gauges register normal, no codes in OBD (AutoZone). Any ideas?
When the vehicle quits or wont start back do you know if it looses fuel pressure or spark to the plugs?
Customer: replied 7 years ago.
no, I don't, the longest it has taken to re-start is about a minute, and 4-5 tries. how would I check for lost spark, or lost fuel pressure?
You would need to hook up a gauge to check for the fuel pressure. As for spark would need to remove a plug and ground it and see if it makes a spark when cranking the engine. Most likely the problem you having is with a failing crank sensor or cam sensor as many times they fail and will not leave a code. It will be hard to diagnosis if it starts right back up. You will have to wait for the vehicle to fail to start to diagnosis it or take a chance and replace a sensor.
Customer: replied 7 years ago.
Is replacing a crank or cam sensor a big deal? Do you have any diagrams or pics?

Both are fairly simple to replace and will take around 1/2 hour each.


The camshaft position sensor is located in the distributor.





The crank sensor is located on top of the transmission bell housing



brownjeff and other Jeep Specialists are ready to help you
Customer: replied 7 years ago.
It was the crank sensor, and it was a bear to get to, but it is done!

Once again you came through! This was the second time I needed help from you and both times you helped. I am telling everyone I know about and Jeff!

Best regards,

Charlie Simmons

Glad you got it!!!

Also glad I could help. I wish you no bad luck but if you need help again just ask for me when asking the question.


Take Care,