With family on their way from Denmark I didn't have enough time to get my Jeep done so I left it alone. Was running great back in January. 180k with warm oil pressure at 40 and burns a quart max between 5k oil changes with full syn. I started it up in the morning, let it idle for about 30 seconds then like an idiot floored it from 0 to 60 and ever since it's had this annoying miss.

Definitely noticeable at idle, causes the Jeep to shake. Light throttle is worst, so between 1000-1800 rpm. Get's better by 2k and gone around 2.2k-2.5k then back all the way to redline. Very rarely it'll smooth out at idle and come right back when throttle is applied, usually when engine is nice and warm. Can feel the shake during deceleration as well. No check engine light either.

Has new tps, map, plenum gasket, cap, rotor and plugs. Today I did a warm compression test and ruled out a burnt valve. All plugs had a very even color, borderline lean. Clean with no deposits. Switched to copper NGK's since I had the bosch finewire's in there. First thing I did back in Jan was check for a broken valve spring as I could hear a faint buzzing ticking rattling noise coming from cylinders 6 and 8. Valve springs were healthy, pushrods straight, rockers tight. Ran the car with covers off and looked like it was normal, nothing obviously bad. Didn't run it too long as it was making a mess.

I'm running out of ideas. I'm thinking lifters since the noise changes at idle albeit very rarely. Would think a washed lobe would show itself in a compression test and not change at idle. Also thinking cam lobe because there's no loud ticking like you'd think a bad lifter would have. Thanks for any help.

 

Are you sure your not fighting a injector issue?
You might try the Sea-Foam Produce Oil Treatment and Fuel Treatment...
https://seafoamsales.com/
Just food for thought....

 

I agree , fuel ejection problem, fi cleaner.
Have fun!!!

 

All the plugs were evenly colored and very clean. New delphi fuel pump and pressure is good.

I'm thinking harmonic balancer. Going to hit that first sometime this week. Will keep you guys posted. Yeah no stored codes since Jan either, was expecting at least a misfire code.

 

Check the miss fire count with a scan tool...

 

If it's knocks hard enough it will turn the light on... At least the knock sensor will turn it on. If its knocking in the combustion chamber, its going to pull timing out...

 

FIXED! New one piece damper and I'm running smooth again!! The old damper looked in tact, keyway in place, no wobbling and very little belt noise some mornings. I wasn't able to flex it much even using a full size pry bar. Hope this saves someone a ton of trouble in the future.

Now what do I do with nearly 6k in go fast parts lol. Thanks for the tips!