My 95 pick up will die off and internally misfire when the automatic transmisson goes to shift.or you can be driving down the road and it will just happen. when it dies if you let off on the gas it will shift then you can go and if you get up to 60 then it will run then just die again. it wont do it all of the time. i've had to the garage and changed the rotor and cap, then the mechanic said he checked the fuel pressure and it was fine, he said he had an error code that pointed to the map sensor so he replaced it, said he checked the vacum ahead it and electrical. it still did again, i took it back and he said he got the same error code and rechecked everything again including the throttel body and noticed a crack in the gasket for both so he replaced and told me to drive it. hep same thing and this after i told him to drive a week to see and he said it drove fine.i also had the fuel filter changed and the rear fuel line changed back in december.
What could it be computor? was the map bad that he put in? this has been going on for five months now.
PLEASE HELP!

 

What code is it? I know this is obd1, but that is needed to determine where to look. MAP sensor will cause it to run like crap, and even quit at altitude, but it should still run.