SureTrack Community Fix: How Many Cylinders?
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Cylinder deactivation is one method of improving fuel economy on a thirsty engine. But they can have issues. SureTrack community member carguru had a Chevy Silverado that had a lot of codes and felt like it had a misfire but couldn’t find any. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
2008 Chevrolet Silverado 1500 5.3L
Feels like misfiring, lack of power, replaced VLOM.
Customer complains at idle, truck feels like it is misfiring. Also has a slight lack of power under normal acceleration.
Diagnostic Steps Performed/Parts Replaced
Scanned truck and found the following codes-P0172, P0174, P1174, P1175, P2270, P2273 and P3425. Watched live data at idle, specifically watching for misfires, and it never registered a single misfire, yet I could feel it shaking the truck. A bulk of these codes are related dirty fuel injectors according to my research, so I ran a cleaner thru fuel system. I cleared codes and for now, the only reoccurring code is P3425, Cyl #4 deactivation solenoid circuit, which comes back on right away. LT fuel trims remain way opposite of one another as well. MAF reading was right on track as well. My main concern is code P3425-Cyl #4 De-activation Solenoid circuit. Do I have a faulty Valve Lifter Oil Manifold (VLOM)? I’ve done a ton of lifter replacements on these from rollers being faulty, but that almost always gives me a misfire code! I have never had an issue with the VLOM before, any thoughts?
Best Answer from Community Member ericsautomotive
You could run the cam and crank relearn procedure. This would confirm the PCM is tracking the correct cylinders. However it does sound like it has a bad VLOM.
It was the VLOM. It was a huge gamble $$ wise, but it was the fix. Thanks everyone.
Replaced Valve Lifter Oil Manifold (VLOM). Test drove vehicle and it operates properly.
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