With those symptoms I'm scoping the ignition, testing compression (and leakdown if compression is unbalanced, natchrully), and inspecting exhaust valve springs. It sounds a lot like a burnt exhaust valve, but it could also be a coil heading south or a flaky CPS producing a soft signal (crappy rise and fall times, low peaks, that kind of thing).

 

Coil was replaced as well last summer... I think.... (it was replaced, just not sure of the time frame.) I have another one yet, as that didn't fix the problem I was having then either......

I am thinkin it's time for a compression test..... but, that is probably going to tell me it's new motor time........

 

Check the fluid level in your Turbo Encabulator.

 

is it smoking at all when warm?

 

Smokes on the first drive of the day, for about a half mile. Yes, I have excessive oil consumption..... about a quart every hundred, hundred and fifty miles or so. The plugs are relatively recent.. but, I guess I will pull them, and see what they look like.

 

holy smokes on the oil consuuuuming!

In your first post you mention oil fouled #8, then you tested with front O2 out that showed improvement (partially). Any thought to clog cat contribution to this?

 

Timing ??

 

A clogged cat might not be causing the miss. With that much oil consumption, I'm thinking worn rings and/or worn valve stem seals.

 

Yeah, valve seals are most certainly toast. The cat was hollowed out before I got it. The oil consumption has improved since the plenum repair... (used to be a quart every 50 miles...) but, the engine only smokes for about a half mile on the first drive of the day.... no evidence after that. Given the sheer volume of oil I am going thru, I would think it would smoke like a diesel..... but no...

I am guessing that it is getting on toward time (if not past time..) for a different motor. I think come income tax, a rebuilt unit is going to be part of the plan.

 

Heck with that. Yank that puppy and rebuild it yourself.