Thanks RT. I adjusted the position sensor, and it didn't make any noticable difference, but as another useful diagnostic fact: it recently got pretty warm here (around 60 degrees. It was around 35 all day before) and the engine seems to run much better when its warm outside. This seems totally counter-intuitive to me. The car shouldn't care what the outside temp is...should it?

1988 Trooper II in the works.