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Ron, ASE Certified Technician
Category: Jeep
Satisfied Customers: 35858
Experience:  34 year working in the automotive field as a Tech.
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I have 2000 jeep 4.7 with codes P0203,P0202, P0205,

Customer Question

I have 2000 jeep 4.7 with codes P0203,P0202, P0205, P0135,P0141,P0174 and P0167. I just replaced head gaskets and am concerned that valve timing my be one gear tooth off. Would that cause these causes to set? Did vacuum check and it is barely on low side making me suspicious of late valve timing? Also considering bad TPS?
Submitted: 1 year ago.
Category: Jeep
Expert:  Ron replied 1 year ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

The code P0202 could indelicate you may have a valve timing concern, so that needs to be addressed first. That would also cause a low vacuum reading, I would recheck the cam timing and then clear the codes and see if any return. Check this and post back with the results and we can work from there.

Customer: replied 1 year ago.
I tried advancing valve timing on suspected head by one gear tooth on the cam sprocket and engine ran but not very well especially at low RPM, so now have returned to original timing. In the process, I noticed two things 1) engine ground wire at rear of engine was loose and 2) head (valve)cover gasket was compromised. Could valve cover leak cause cause unmetered air to set codes?
Expert:  Ron replied 1 year ago.

Yes a valve cover that not sealing would be an unmetered leak and this could set a code. Any air that enters the engine with out coming through the MAF sensor will set codes.