Volvo: Volvo 240 electrical, auto electrician, odd intervals

Question
Hello, I drive a 1991 240GL automatic volvo wagon. A few weeks ago a dashboard light (green and orange) came on telling me that there was a problem with either the iginition or exhaust. It then began to stall at odd intervals. I had it checked twice by mechanics to no avail. Then the other day it would not start at all. I took it to a auto electrician who told me it was the computer, and put a new one in. It was fine for about 24 hours, then the same problems began occouring again.

Answer
Cassie,
More tests will need to be done, this time get the car to a shop that works on Volvo's. Did this tech read the fault code? What were they? Best advice go to a Volvo shop. There could be air mass meter problems, engine miss due to ignition faults, low fuel pressure a faulty per pump, so many possibilities. Needs better fault tracing.