Have a 2015 Sierra w 5.3 and have been getting P0306 cylinder 6 misfire. Replaced the coil pack a week ago and it seemed to fix the problem, it ran fine again. Yesterday, I was towing my travel trailer home and the misfire started happening again, same cylinder. Took it into dealership and they checked a few things, but not a problem with coil pack. Mechanic is thinking it might be a collapsed lifter and may have damaged the cam....ballpark $7k to fix and of course the truck is out of warranty. Seems pretty crazy to be looking at a repair like this when I just turned 68K miles!

If I do have to replace the cam and lifters, I'd rather do a few performance upgrades, maybe a stage 1 cam and dod delete kit. Does anyone recommend any shops in the DFW area that would be able to do install? Maybe near Sherman, TX?

Any other upgrades I should consider at this point?

Thanks!

 

Pretty common failure.

Biggest thing is to stop driving it.

$7k to fix? JFC that is a markup.

 

Think the $7K number from mechanic was to replace whole engine. They were gonna charge $1,300 to fix lifter in affected bank and would give 2 yr warranty. Decided I'd rather go with cam and dod delete option and not worry about lifter collapsing again, so taking it to different shop. Found one that will do work for around $1,500 with me supplying all parts and another $500 for tune.

Ordered cam install kit, ported heads, and l86 intake upgrade from GPI. Hopefully that gets me back on the road with a little more power. Maybe long tube headers and y pipe to finish it out later down the line.

Anyone have any feedback on GPI cam or heads?

 

call Bret @ LS Performance in Forney. he mainly does vettes, but he's an LS magician & an excellent tuner.
972-741-7457