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rpmdiag, Tech and Instructor
Category: Jeep
Satisfied Customers: 8134
Experience:  Since 1975
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I have a 2000 grnd Cherokee ltd with a 4,7 ,123,000 miles on

Customer Question

I have a 2000 grnd Cherokee ltd with a 4,7 ,123,000 miles on it , it runs great in cooler weather but in summer temps, 80 degrees or higher it stalls out and dies during normal driving conditions. I am a decent mechanic with 20+ years millwright experience. Car is well maintained, I have tested fuel pressure and it runs at about 60psi fuel pres. at fuel rail, replaced filter/reg twice, also has air in fuel system from pump, not sure if that is normal but sometimes when it shuts down I can bleed off pressure at fuel rail till all fuel and air is gone and it will start, other times it seems to have to cool off for a few minutes and it starts back , but in city traffic in hot weather it will repeatedly shut down, its insane, I have been able to diagnose and fix every other car I have owned except this one , PLEASE help , my wife drives it to work daily and I'm afraid she may have an accident because of it shutting down.
JA: How many miles are on the car? Have you had the fuel pressure tested recently?
Customer: I just said it has 123,000 miles odo. and I have tested fuel pressure many times , it runs at about 60 psi , normally it should be 45 to 54 psi, changed filter regulator and tested the return line to make sure it is not blocked, it was fine, but did notice air bubbles coming from return line with fuel.
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Yes, I have changed the TPS, cam sensor, crank sensor, fuel filter regulator twice, checked fuel pump relay, checked fuel psi many times.
JA: Anything else you think the mechanic should know?
Customer: There is nothing left other than control module and fuel pump. I am thinking about replacing fuel pump next, but not sure if it will fix the problem. With too much pressure at fuel rail and air in fuel line that seemed to be the obvious choice , but at 150 bucks aor fuel pump I want to make sure first, I'm tired of guessing. This aint my first rodeo.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Jeep Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Jeep
Expert:  rpmdiag replied 1 year ago.

Hi, I’m Ron and I can help you.
I have been in the auto repair business with my own shops since 1975 and also teach automotive repair. I am confident we can resolve your problem together. Please understand that I don't know your skill level. In most cases when you have a problem with the way the vehicle performs, specialized tooling is required to acquire computer data/information or engine testing results. We didn’t build these complicated vehicles; we just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the vehicle either, so it may take a few replies to get to satisfactory results. I am also going to direct you with the fastest, easiest and most common things to check first. Please be patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in return. I will also continue assisting you after you have rated me, if necessary. If there is any reason I cannot get a positive rating, please let me know why “in advance”, so I can go another direction for you. I am sorry you’re having this problem; I’ll help you through it.

I would check the fuel lines closely, then drop the tank to search out where this unwanted air is coming from.

Thanks, Ron