1991 volvo turbo 290k car stalls then restarts

[Henry D]

The car has always upon starting up runs on less than full power then it feels like it kicks in another cylinder and after that it runs fine. Lately on a very rainy day in slow traffic it stalled and would not start right away but kicked over and ran rough off and on until I got out of the rain then it was fine and I got 23 mpg the best run ever. I started it 2 days later and was fine turned off about 10 min later to get gas and would not start very good weather. It chugged but would not catch enough to run. 10 min later started and I drove to maine with no further problem. 5 days later it ran fine for 1 hour good weather. The next day It started fine in some pretty heavy rain. Ran fine for a hour or so then I hit a bump in the highway and it lost power but if I put the peddle to an even place and kept it there it kept up the speed if I pushed it it faltered. I keep it going approx 70 mph and hit another bump again lost power. Then back to the same peddle location seemed to pick up and start running again. Then after a while all was well with acceleration. I put a new tank pump in 2 years ago and the tank was 3/4 full when all this happened except the earlier 10 min 10 min where i filled up. The relay was resoldered several years ago the pump was sounding when the key was turned. Distrib cap and rotor wires and sparks changed about 15k ago.
Where do I look for the fault. MAF sensor. Hall sensor. Fuel

[sanfelice]

I had an 86 760T and that had a severe problem with the ignition control module which, on that car, was mounted to the driver's side inner fender. The symptoms that plagued those units were slightly different from what you describe, though. The problem was cutting out all at once and then restarting when the module cooled. If I were you, I may suspect water in the distributor cap, if you are experiencing this while it is raining.

[Henry D]

It happened both with rain and with out I will check the distrib cap and see