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Pete, Technician
Category: Jeep
Satisfied Customers: 27813
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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I have a problem with my 2008 jeep jk, it drives perfectly

Customer Question

hey there,i have a problem with my 2008 jeep jk,it drives perfectly fine if i drive it smoothly, if i push the gas pedal all the way, the first gear drives fine, 2nd drives fine, on third gear it starts hesitating and no power to accelerate, if i release the pedal and push it again it gains power again, then when it reaches to a very high RPM it starts misfiring...these are the parts that i've changed so far,
1- PCM
2- Crankshaft position sensor
3- Fuel Pump
4- PCV valve
5- Coil and wires
6- spark plugsand im still facing the problem..please help
Submitted: 1 year ago.
Category: Jeep
Expert:  Pete replied 1 year ago.

Hi,my name is ***** ***** I will be happy to try to assist you with this.I may need more information in some cases to help with answering your question.

Expert:  Pete replied 1 year ago.

One very common component that will cause this issue here that I have seen is a faulty catalytic converter.It will restrict internally partially and at higher speeds/rpm it causes a lack of power or misfire like this here until you release the pedal to relieve some of the back pressure built up and then it may work for a short time and act up again as back pressure builds in the exhaust.

If you have not had the exhaust back pressure tested at all this needs done.If there is severe back pressure the catalytic converter assembly will need replaced.Your back pressure should not exceed 1.5 psi at any rpm range.You can usually rent a back pressure tester from a local parts store to do this testing.It threads into the oxygen sensor port before the catalytic converter.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
hi Pete,well, i got the catalytic converter gutted out.. so it's completely empty from the inside, any advise?
Expert:  Pete replied 1 year ago.

Have you tested for a loss of spark or fuel at all when this issue here occurs?

Customer: replied 1 year ago.
the problem disappears when I park.. so how can I test it?
Expert:  Pete replied 1 year ago.

O.k.,my info is not listing this engine on this model here myself.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete