You can do a search under my name if you want to know the details of how it runs but for the most part it feels rough and sounds very different than it used to. It also has a missfire at idle most likely from the same cylinder and not every revolution. It also runs rich according to datamaster, long term fuel trim is 115ish, car gets an average 200-210 miles per tank pure city driving regardless. I thought it was injectors but they dont leak and pressure is good makybe they stick? Car has 95k on it and problem came around about 80k or so. compression is 160-175 on the drivers side and it sounds like the missfire is on the passenger side which I cant test because the longtubes are in the way. BASICALLY what would a sticking or collapsed lifter/s make an engine do?

 

Beuller....Beuller...........Beuller......

 

After setting for a couple days does it peck when it is first started? If so does the pecking go away after it warms up?

 

Engine doesnt make any noticable noise and actually idles better when cold. It still runs sub par and sounds terrible but the idle has far fewer missfires when just started in the morning.

 

My Impala SS is doing basically the same thing. Cold it sounds fine. After it starts to warm up and the oil gets thinner it begins to tick. I am pretty sure it a lifter bleeding down. Just bought a new set of GM lifters with new retainers and spider. Also ordered a set of Isky adjustable guideplates. We will see if it fixes the problem.
HVY SS

 

did it fix the miss ?

 

A collapsed lifter will clack like hell.If they are making no noise then the lifters are probably OK.
The valve adjustment may be too tight,but ya got to go a lot of turns to do that. I set mine on 1/2 turn.
Ya probably need to look elsewhere for your miss if the adjustment is correct.

 

Ive never messed with the rockers they are stock, what would an overpressurized lifter do? would that be an all the time miss or could it be intermittent (sp)? Ill see if I can get some video of the car at idle and the car driving and WOT and get some old video of when the car ran perfectly to compare it and see if anyone can come up with anything... its open headers BTW so it will be very obvious how different the sound is Ill work on getting the new video if someone can help me host it...

 

It is not likely a lifter pumped up and stayed there.
Ya need to do a comp test on all 8 cyls and inspect the springs for a broken one.
If ya do a leak down test and compression test it will show if it's a burnt valve. Then ya need to check the plugs and wires. While ya are under the valve covers check for a flat lobe on the cam.(valves not going up and down the same amount) Cut open your oil filter and check for metal that might have come from a broken roller lifter.
There are a bunch of things to check before ya go rippin and tearing.

 

overpressurized by the rocker nut being to tight will take all the cushion out of the lifter and eventually grenade the lifter internally or the roller tip will flatten and kill the cam lobe. it will also run like crap because the valve never closes

 

Thank you for the replies guys, Ive tested the ignition system with a spark tester also the compression seems to be between 150psi and 160psi on most cylinders, none below 150, except the first time I checked the number 2 cylinder it read 125 but checked it 2 more timesand it read 150 both others so maybe it was a fluke. I checked it when the engine was almost stone cold, well it was about 60 degrees out but you get the picture. I have my oil analysis done every change and have yet to send in the most recent batch so that will tell me what exactly if anything is wrong internally. I know hte drivers side does not have anything broken under the valve cover and all the parts moved smoothly, I didnt check the other side since its not making noise just missing and its a pain but chances are ill end up doing that before I ripp into the engine or anything.