The MIL came on again about 3 weeks ago and I broke down and bought the Air Mass Meter online for appx $310 on line (thebenzbin.com). After installation (I also replace air filter while I was in there) the long term fuel trim immediately dropped to 128% during a 3 mile drive around the block. It has been 3 weeks and about 500 miles and all is well. I replaced spark plugs and fuel filter this past weekend and it seems to be running perfectly. Thanks for everyones help.