Looking for some diagnostic help here.
When I run my truck at interstate speeds for more than a few miles, or load the engine for a mile or 2 (like a long hill), I get some serious valve pounding. Not sure if a valve is sticking, a lash adjuster is sticking/not oiling, or perhaps sucking a valve a bit (not enough to hit the piston, if so)? Along with the obvious hammering by the rocker, the exhaust gets very loud and mean sounding (like the sound, but not good), and I feel a not insubstantial loss of power. Also noticed that the next day I will get a SHITLOAD of carbon out the tailpipe at startup. Leaves a big black skid mark on the ground. This is an intermittent problem, if I shut down and let the engine cool, it usually goes away. I can also just slow down and drive ~40mph on surface streets for a while and it will go away.
I've also noticed that if I let the truck idle all the way up to operating temperature, this is less likely to occur. Not that it won't, just less often.
Noticed when I fired up my truck this morning, my high idle is gone. I mean, just gone. Engine fires up fine, but idles REALLY slow (~250-300rpm). Checked my choke lead, it's still connected and getting power. This one is a bit odd. Truck still ran fine, but wanted to die at stop lights until it warmed up.
I post both of the issues in one thread because I get the sneaking suspicion they may be related. Not sure, though.
Thanks for the help!