Ok, your idea about the fuel mixture adjustment is good but you need to make sure that the adjustment is done properly. A lot of times what I see is mixture incorrectly adjusted in an effort to lower the idle speed. If the car is idling too high that needs to be addressed separately from the fuel mixture. I would have the mixture checked and if leaning it out results in a too high idle then the idle control system will need to be diagnosed. You've had a lot of work done to the car already. One thing I would want to make sure of is that the camshaft timing is correct but I'd only address that if these other things didn't turn anything up. Start with your adjustments and let me know what you come up with.
Thanks for allyour help. I am glad that Iam on the right track. Hopefully, my mechanic will get the adjustments done in the next day or two. If that doesn't do the job, I will suggest
the camshaft timing. I would like to let you know the final outcome. How can I get back to you with that info?