I’m having issues with my E300 1991 M103. Runs great at cold start but the warmer it gets the less I throttle I can give without choking/stalling it. It really feels like it's running too lean, more starvation the warmer it gets.

If I continue driving it (lower and lower speed to avoid stalling it with too much throttle) until full operating temperature it eventually starts to run poorly even on idle. If I then turn it off and restart it immediately, it backfires some and takes 5-10s before it starts and runs poorly.

If I wait until it's cooled down it runs great and accepts full throttle again.

Has anyone else experienced this problem?