2013 GMC Sierra 1500. Currently at the dealership:
SCAN AND FOUND P0304. CHECK AND FOUND IGNITION COIL FIRING. CHECK AND FOUND NO COMPRESSION ON #4. REMOVED VALVE COVER AND FOUND BENT INTAKE PUSH ROD. RECOMMEND ENGINE TEAR DOWN AND INSPECTION FOR LIFTER/CAMSHAFT DAMAGE. $800
Unfortunately, misfire happened on the way to work, so it's probably done 50 miles since it started misfiring.
So I'm going to take it home 5 miles and try the lifter release method. Perhaps AFM delete if it comes to that.
Would it be better to drive it the 5 miles with:
New pushrod
Bent pushrod
Removed pushrod?
Thanks,
Bob
No, but definitely don't turn key on with battery hooked up and ECM out. It will trigger a bunch of communication codes in other modules. Don't forget to disconnect battery again to plug ECM back in.
Yes, the ECM needs AFM shut off in the tune.
When I replied last time that video wasn't available. Not sure if you added that later or not but clearly that looks like a collapsed lifter or bent pushrod. It's not likely you have both a spun lifter and a collapsed lifter though it is possible. You wouldn't be able to tell without uncollapsing the lifter first. The tool is designed to release that collapsed AFM portion of the lifter. So it looks like your next step is to release the lifter.
The floppy rocker would have to be checked with a good pushrod installed. That doesn't sound like the rocker is loose from collapsed lifter though. That's a very subtle tick at most from the device I'm listening on. At most it might be a bad spot on the lifter roller but incredibly hard to say based on that video. If you have it in a shop for diagnostic what have they said so far? Doesn't even look like it's misfiring actively. At least not badly. I see a little bit of a shake there.
Best to drive removed pushrod on both intake and exhaust. But you will also want to unplug the fuel injector. I recommend verifying the lifter is collapsed and not damaged prior to the lifter release attempt.