2006 Chevy Silverado 4.8l w/61000 miles, misfire cylinder#1

[ecar larry]

Just thought I would share this. About 2 weeks ago we had a customer come in with the check engine light on.

 

We pulled the code P0301, as I was writing up the work order he told me he had just come from the local dealership and they told him that they found 2 codes,P0301 and P0308, then told him that it would cost 375.00 to diagnose the cause of the misfire, he agreed, 2 days later they told the customer that he needed both heads replaced at a cost of 8400.00, (OUCH) the customer then asked me if we would give him a second opinion.

 

We went through and checked the basics, all was good, compression 10psi low on #1, leak down test good, and thats when the head scratching started, keeping in mind that the truck only had 60,000 miles on it internal mechanical failure was not on our radar.

 

After quite a bit of research, we came across a "SI" or as we call them a tsb with regards to the intake cam lobe on the #1 cylinder wearing due to lack of lubracation at idle, we measured the rocker travel and we found a full 1/32" between cylinders 1 and 3.

 

Replaced the cam and all 16 lifters, no more misfires, truck passed smog and the customer is a happy camper.

 

I have to say in the 21 years we been in business I have never had to replace a cam for a misfire.

 

Any of you guys or gals came across this?

 

Thanks

Larry

[CARMandP]

Just enough difference in the compression to cause the computer to pick up the misfire. Crazy. Thanks for sharing.

[ecar larry]

The compression was not the problem...the worn cam lobe and lifter was. Still crazy

[Jeff]

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