I have a wonderful '86 sedan with 324,000 miles on it. It has the original automatic transmission and engine and is pampered with its major service every 25,000 miles and oil changes with Mann filters every 2500 miles. I drive it to work 90 miles round trip every day. It's due in 1000 miles for it's next major service and the last week has been stalling when first started and put into gear. It doesn't matter if it's first thing in the morning or when I'm leaving in the afternoon from work. If it's been sitting for more than a few hours, this problem occurs. It will start right up when I try it again. It has never done this before. Is there something I should pay special attention to when doing my up coming tuneup, or is this just age (time & miles). I' really looking to the day in three years when I can mount my 400K mile badge.

Thanks in advance.