I have an 91 Audi 100 (2.3L?) with almost 200K miles that feels like it's choking out when I accelerate from stop to start. If I ease up on the gas pedal or softly pump the gas pedal it will not stall and will slowly move forward and once I am going it is fine. I had a problem previously in that it stalled out and couldn't be started gain the day after I took a 9 hour trip. They replaced the regulator, but I'm not sure that was the problem as the problem was very intermittent back then. It has also stalled a couple of times when I was going about 30 mph and had taken my foot off the gas to begin to come to a stop. The catalytic converter was replaced 4-5 years ago, it was recently tuned up, fuel injectors were cleaned, intake (boot or manifold?) were replaced, fuel filters were replaced, distributor cap, etc. Also, the problem seems to be getter worse. Probably unrelated, but the speedometer needle in the last 6 months has started bouncing back and forth within 10 mph when I'm driving, but I'm not feeling or hearing revving up and down while it's doing it. From reading the forums, it sounds like it might be the throttle position sensor, or oxygen sensor? My mechanic has no more suggestions on what could be wrong. Help!!

Fuel pressure been tested? Does this car have a Mass Airflow Meter? sounds like one or the other