My wife's 2009 Yukon Hybrid started running really rough on her as she was driving down the interstate the other day so I had it towed home assuming that the P0307 code it was showing meant I had a bad ignition coil. I swapped the coil with #5 and changed plugs and wires for good measure, still had the miss. While I had it in the garage I decided to change the valve cover out tot he square hole design to see if the oil consumption would get back to a normal range per the TSB and found that the #7 lifter is DEAD. Has anyone replaced the lifters on these? does anyone have a parts list for the DIY'er? shop cost?

 

Called around this morning, GMC dealer is estimating $2400, Chevy dealer just had one come through, 5.3 L, and the cost was $2200. Local shop quoted $2400 as well. Book time to do both banks is 11.75 hours for the hybrid and I can get the afm lifters for $69.21 and the regular lifters are $30.81 I also need the valve trays and gasket sets which completes the parts cost.

 

I had to get my lifters replaced 4 months ago because of a misfire in 8 (P0308). The labor on the even number side of the engine is a LOT higher than the odd number side because of the hybrid components in the way. Mine cost $1600. It it an occasional misfire or 100% misfire? I just took mine to the shop AGAIN where Cylinder 6 is 100% misfire, most likely due to a failed injector. The occasional misfire is likely a stuck lifter due to the AFM. Did you get a compression check?

 

Since you sound handy enough by taking off the valve cove already maybe you could try before spending money on replacement lifters, giving them a cleaning to see if you can get them unstuck internally as sticking is sort of a common problem. If interested in trying to clean them there are many okay videos online on ways to give it a try. Below are 2 examples for you to consider or just try video searching "How to clean stuck GM lifters in a 6.0 AFM" for other videos like it.

This is more of a how to replace the lifters video.

Also don't forget to change out the little filter that sits under the oil pressure sending unit that's basically for the AMF valve lifter system as it will cause you lifter problems too.