Hi, I am looking for some assistance with diagnosing a very annoying vibration problem in my 2002 6.6 Silverado. I have recently noticed this heavy vibration at idle and just off idle. It comes up through the seat, steering wheel, and pedals. The problem goes away or at least is not noticeable once revs are up. I am wondering if this is an engine mount problem or injector misfire or something. I recently had to take the truck through it's bi-annual emissions test and it passed with ease so not sure if injectors would be the problem although the engine is noisier now than it used to be especially under load. I had put this down to the synthetic oil I switched to useing which is Mobile 1 15-40 diesel and says it is recommended for the Duramax.
According to my truck history printout there was a left and right upper cushion/body shim replaced by the original owner at 48,500 Kms (part # E1103 E1104). Would this be something to do with a vibration problem previously? The truck now has about 178,500 Kms on it and appears to have the original injectors although according to the printout the fuel tank pump module was replaced at 30,800 Kms Truck has also had the powertrain control module reprogrammed with SPS at 57,000 Kms. What is this SPS and am I up to date with programming??
Any insight into my vibration problems would be appreciated. Thanks in advance.
Cheers,
Bruce
2002 Silverado Duramax extra cab short box 2wd