AC Delco fuel pump. The filter was changed at the same time. The mechanic said it was clean, as was the tank. Usually the car stalls when it is hot. But, it has stalled after only running for a couple of minutes. It actually stalled that time when I was sitting at a traffic light about two minutes from my office. However, that has only happened once. It never stalls or sputters on acceleration. Something else I have noticed when it acts up, the oil guage goes haywire. Also, sometimes when I am driving with the cruise on, it just shuts off. This, I've noticed, occurs when I'm rounding a curve. I haven't had any other serious problems with the car and this one is very intermittent. One friend suggested it might be the opti-spark. What do you think?