2010 Suburban, 4x4, LT, 240,000 miles. It's always used oil. Check the gas, fill it up with oil. Then one day smoke poured out the back. Take it to my mechanic (who's always worked on it and been fantastic), he says it needs a valve job. So while the valves are sent off, we decide it's a great time to replace the lifters, piston rings, and even the cam shaft. Why not. Get the new heads and at idle and reverse the truck shakes like crazy. Very low oil pressure. Send it back, they decide its a bad valve job and get another set. Same thing. Replace the oil pump, intake, throttle body, even the valve covers with the new updated ones and an oil catch can. Still shaking like crazy. Mechanic takes it to the dealer, dealer says bad valve job. Do a leak down and it'll prove it. So I'm on the third set of these things. Surely I've not had two bad sets in a row, right? Before hand the truck ran great. Fantastic oil pressure, no jerking and moving. But after this it's been a nightmare. The oil pressure dropped so low one time that the light came on. Wife was in Starbucks drive through. We all got cussed that day.

Any ideas? I've asked about motor mounts and transmission mounts. I'm stumped. Then again I know very little.

 

Looks like whoever is doing the headwork is not doing good work. At 240k miles and truck is a rust free southern / western truck I'd would just do a complete motor and be done if truck is worth keeping. I'd price a fresh motor since it's at the dealer I believe GM has a good warranty on motors.

 

Was this a valve job or reman heads? What is the compression numbers on each cylinder? Did you do an AFM delete? Almost sounds like they installed the wrong camshaft or you did an AFM delete and didn't have the computer tuned.