89 pontiac 6000le accelleration issue

The problem that I am having with my car is that every so often when I start the car it stalls out when I put it into gear and press the gas. Every time I bring it into the mechanic it doesn’t happen when it’s there. On one occasion he did have it happen but when he tried again and again it wouldn’t rear its ugly head. He said the fuel pressure is fine and can’t diagnose it unless he can get the problem to repeat itself. I did have the fuel pump replaced about a year ago. I am hesitant to take the car out for use knowing that this can happen at anytime. I can always start the car but it just stalls when I press the gas. Other times it runs fine. The mechanic had the car for three days and put about 60 miles on it but could’nt get it to happen for him. Any ideas as to what may be causing this problem?

Does it appear to happen when the vehicle has sat for awhile or on the first start of day? If so, the problem might be with the coolant temperature sensor for the computer.

Tester

It can happen at anytime of the day regardless of whether the car has sat for a while. However, I usually encounter it first start of the day. When it does happen it repeats several times. The strange thing about it is that I had left the car with the mechanic for three days and yet it wouldn’t happen for him. He’s tried it first thing in the morning when they open and intermittenly throughout the day. Only could get it to happen just once and not repeat as in my case.

The mechanic finally got the problem to replicate itself several times and it showed that the coolant temperature sensor was bad. It also showed a couple of other sensors bad but it eventually came down to the computer being bad. Hope that takes care of the problem once and for all. Will keep you posted.