amg280 - I tried a cylinder isolation approach by disconnecting the spark plug cable cylinder by cylinder. I could not isolate a bad cylinder.
The mixture is something I'll look into. The problem there is that this is not DIY - you need something to read your exhaust emissions for this. Before I take it to the shop, I'd like to narrow it down. I'd hate to take it in, have a mechanic do the mixture, it not work, he tears the whole thing down and tells me it need a new fuel distributor, when all I really needed to do was clean the screens and replace a fuel line.
I wish I had my own shop, lifts, scopes, everything...