Ok guys. Thanks for all the help. Time to put this thread to bed. Yes, it turned out to be a bad MAF - as per the high reading (16) which according to Eric is about twice as high as it should have been at idle. The high MAF value was making the ECM throw twice as much fuel into the engine - making it run super rich. As a test, Eric said to make a log with no MAF (the computer would assign a base value). That leaned it out a lot. Instead of seeing 7 to 1 A/F in the Powerlogger, it was about 15 to 1. Because my TTA has an ACCEL Gen 7+ running it, I had a spare MAF that I forgot about. I just installed it and the A/F numbers are now about right. Not perfect, but at least I have the car running off of dead rich which is something that I can work with. I will install a new set of plugs and re-check for any possible vacuum leaks. But chances are that it just needs fresh plugs.
When I was trying to troubleshoot this problem in the previous engine, I borrowed a friend's MAF and saw no difference in the way the car was running. But by the time I tried that, the spark plugs were most likely badly fouled out. It's also possible that my friend's spare was no good. Back then I knew nothing about typical values for MAFs at idle. I didn't have enough experience with MAFs. I am used to the speed density system in the TTA.