1991 GMC Sierra starts, then stalls when hot
 

hey ya'll,

my brother has a 1991 GMC Sierra... it has the 5.7 engine.

it starts and runs great when cold. idles nice and smooth.

when the engine is hot and has sat for about an hour after shutting off, it will start and stall and be very hard to start. the problem only happens on hot summer days. if the truck sits long enough to cool off, it starts and runs normally.

Re: 1991 GMC Sierra starts, then stalls when hot
 

If start by unplugging the timing advance wire, it should be on the passenger side by the firewall, and see if that allows it to start again. Then I'd check the coolant temp sensor as when they fail your PCM thinks its cold as hell and dumps fuel trying to warm it up.