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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29396
Experience:  GM Grand Master Technician 2007. 14 years experience.
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my 2002 gmc envoy runs good by it has a vibration at idle any

Customer Question

my 2002 gmc envoy runs good by it has a vibration at idle any ideas we checked the fan and the drive acce
Submitted: 7 years ago.
Category: GM
Expert:  GM Tech (Cam) replied 7 years ago.
Welcome. Is the check engine light on? These engines have been plagued by issues with the intake valves sealing to the head. This results in a higher than expected cylinder leakage, and actually causes slight misfires at idle. Unfortunately the repair if this is indeed the case, is to replace the cylinder head and valves. The way we test for this is a cylinder leak down test. With a cylinder top dead center, we put compressed air into the cylinder using gauges, and we see what amount is leaking. Anything more than 25% is excessive.
Customer: replied 7 years ago.
the service engine light is on when scanned it said that the cam sensor was out of phase
Expert:  GM Tech (Cam) replied 7 years ago.

That could cause this as well. Do you have the code number?


Customer: replied 7 years ago.
no We cleared the code and then it came back a day later
Expert:  GM Tech (Cam) replied 7 years ago.
Ok,. This is something that you need to correct. The cam phaser or the actuators can cause errors. IF you can get the exact code, I can better advise you.
GM Tech (Cam) and 3 other GM Specialists are ready to help you
Customer: replied 7 years ago.
we will scan it tomorrow and get the code is this the sensor on the right side of the engine in the fornt at the timeming belt area
Expert:  GM Tech (Cam) replied 7 years ago.
There are 2, one for each camshaft. I am going offline for the night. I will be back on in the morning .