I have a 94 gmc 1500 and a few weeks ago I started having issues with it starting. One day it would start fine and the next day it wouldn't. I changed the fuel filter thinking this was the issue. The truck did fine for a week. The other day it wouldn't start again. Cranks really strong but just wouldn't start. Set for two days then went to start it and it started on the first crank. The fuel pump is running when the key is turned on. Any ideas?

have to try to narrow it down, see if its got spark and look at the fuel spray

ignition issues sounds like to me

Ignition module?

Could it be the distributor cap, wires and plugs?

could u possibly have a fuel pump relay getting hot? some vehicles depending on where the relay is put can be exposed to very hot heat which could make the vehicle start in only special conditions.. for example it may not stay at 90 degrees outside but would start at 45 degrees

Not sure. Just odd that it starts fine one day and not the next. Not sure where to even start with this issue.

you have to try to get it it to fail and when it does then you have to look and see what it has and doesnt. take the air cleaner off and check the fuel spray should be decent cones not dribble. pull a plug and see if you have spark. there is a little module in the base of the dist thats a pretty common tbi engine failure