Car stalling

My 1998 car which has done me quite well has been stalling. The engine shuts off while driving. I took it to the Honda shop and they said it was the alternator. I got a new alternator, then a week later I had the same problem. The Honda shop did additional work and the problem still occurred. Then I took it to a local Sunoco station, they found that my ignition was loose from the weight of the keys. So they tightened the ignition area and told me to keep my driving key separate fro my other keys. The problem appeared to be solved. Unfortunately about two weeks later, my car stalled again. I took it back to the Sunoco station and they are going to give me a new ignition. I’m still not certain if that will fix the problem. A friend said that I might just need a new distributor cap. Any other thoughts or suggestions? Thanks.