Problems w/a 1985 celebrity

I have a 1985 chevrolet celebrity 4 cyl. w/ 65000 miles i change the oil every 3000 miles since i got it with 43000 miles from my son in law who bought it from a lady who didn’t drive anymore,the problem started 6 months ago when the car die in a busy street i was towed to a shop and they told me it needed a new fuel pump along with 2 sensors (relays) 1 for the AC and the other one for the fuel,the problem went away but it came back and now when i have the AC on and i try to put in gear (doesn’t matter R or D) the car dies,i have to star it several times without the AC on but i need the AC because i live in south TX, now the mecanic said it need a new fuel pump because he cleaned the injectors last week but it didn’t help the problem,i also changed the 2 sensors (relays) but nothing improve,please help me i’m retired and i live in a fix income and i can’t spend $500.00 very 6 months and i can’t afford a newer car.and the mecanic also said the fuel pump need to be change becuase it gets really dusty around here

first of all, get a new mechanic. Seriously. He replaced your fuel pump, and then says he has to replace it again because he cleaned your injectors last week? Unless you are not telling use everything, you need a new mechanic. Did he check the fuel pressure to see if was proper? Did he try replacing fuel filters, or checking sensors? And dust should not affect the fuel pump, since it is in the gas tank. And if dust is a problem then your fuel filters would be clogged.
And there are sensors that also help regulate the speed of the engine when the A/C is on. Many things to check before replacing the pump.

Just on the off chance it’s the same thing:

I had a 1985 Pontiac 6000 and it would die when the car got warm. Ignition module in the distributor.

BTW, Coffee is right - new mechanic!!

Agree, you need a new mechanic. Also agree that it is not the fuel pump. As I recall, this car has a throttle body fuel injection (TBFI) system, not a MPI that we are most familiar with, so I have a much more limited experience with this, although my daughter used to own one of these also, but that was some time ago. All in all, it was a pretty good car, went almost 200k with poor maintenance.

I can’t remember how the idle was controlled with TBFI but I believe that is did use the computer to control the idle. And the idle could be overridden by a mis adjusted idle stop. If not, then the AC probably has an Idle Up solenoid that may not be working. That is a solenoid that increases the idle speed when the compressor kicks on to keep the engine from dying. Either way, it should be an easy and inexpensive fix for an honest and competent mechanic. The mechanic will probably spend more time looking up the idle control system in his manuals than actually fixing the problem, the TBFI wasn’t around all that long and there are probably a lot of mechanics that have never worked on one.