Ruff S4S

[goodgod]

Hello Folks,
I have a problem with my 1996 S4S. It is running incredibly rough even from cold. The O2 sensor was replaced but has not helped -- not surprsing as the misfire was there from a cold start. However, I've checked plugs and leads and all seems fine there. Interestingly it seems to take off fine (with no shuddering) if you give it a lot of throttle, but if you then try to cruz, the engine bounces around like a demented kangaroo. I'm about to take it to the local Lotus dealer (my wallet is quivering in anticipation!) but I thought I'd try the Forum to see if any other S4/S owners had experienced similar problems and might suggest a solution or two.