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P300 codes 301grand Cherokee

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P300 codes 301(###) ###-####grand Cherokee...
P300 codes 301(###) ###-####grand Cherokee
Submitted: 2 years ago.Category: Jeep
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Answered in 2 minutes by:
1/16/2016
Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago
Brad
Brad, Jeep Dealership Tech
Category: Jeep
Satisfied Customers: 8,332
Experience: 19 Yrs Chrysler/Dodge/Jeep. ASE Master (L-1) Certified
Verified

Good afternoon and welcome to JustAnswer!!

What is the compression for all cylinders? Also what is the fuel psi and when did this start?

Talk soon,

Brad

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Customer reply replied 2 years ago
Fuel pressure is 44 psi with key on and 50 psi with car running. While car is running needle shakes a little. Did not check compression
Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago

Can you check the compression so we can make sure the base engine is ok.. Also if you erase all the codes and start it do all the codes come back active?

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Customer reply replied 2 years ago
150 psi in all cylinders the codes clear and will come back on after 10 miles or sometimes longer been going on for a few months
Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago

If the misfires codes clear and it's an intermittent issue then it sounds like carbon on the valves.. Can you decarbon the valves following the PDF I attached to see if it resolves your issues? Because it sounds like your base engine is ok and if it were a spark plug or injector then it would misfire all the time..

I hope this helps,

Brad

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Customer reply replied 2 years ago
Don't understand what # ***** is. How can I get carbon of valves
Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago

What are you referring to a #39? It basically says to spray decarbon into the breather and allow it to soak 2-3 hrs and then drive it in low to keep the RPM"S up to flush out all the additive and see if your issues are still present..

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Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago

I see this question is still open.. If you need more assistance feel free to reply, and if not then don't forget to rate so I'm compensated for my time..

Have a greatday,

Brad

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Jeep Mechanic: Brad, Jeep Dealership Tech replied 2 years ago

If you need more assistance feel free to reply and if your all set I would greatly appreciate a positive rating so I'm compensated for my time..

Have a great weekend,

Brad

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