1987 Chevy S 10 2.8 litre 4 wheel drive

This has been going on for about a year and a half
and is worse in the summer.

After a drive usually on the highway
I sometimes make a stop at a store and shut the engine off.
The truck will start no problem but shortly after
leaving it will conk out.
This happens in under a minute, I do not make
it out of the parking lot.
I open the hood, wait 10 minutes, then the truck starts
and I leave with no problem.

So my solution is to open the hood when I stop..

Yesterday I replaced the oxegyn sensor
in hopes tis may help the problem
which it did not.

The engine light has been coming on since
I bought the truck.

I replaced all the electronical components
to no avail, it was a improvement
for a short ime.

I put the truck on a computer at a local shop,
he said I need a new oxegyn sensor and EGR valve.

I looked and the EGR valve was not hooked up
would this account for this problem?

Yesterday I had new tires put on and
it conked out backing out of the garage.

A mechanic spayed some carborator cleaner into
the fuel ignition and started.

He said my fuel pump is going, but this has
been happening for a while and it
seems to have something to do with heat.

Thanks

Kevin