1996 Bravada wont start

It runs great for a few months, then when theres a weather change, it wont crank. For ex: last night i drove it home, parked it, it rained all night and got about 10 degrees colder. This morning i went out to try to crank, itll turn and turn, but wont start. Recently replaced oil, oil filter, battery, spark plugs, and air filter. Last year i replaced the fuel pump, and filter. The check engine light has been on non stop for a few months now. Thanks

1. Did you use a cheap pump? All cheap pumps seem to fail within the first year. AC Delco (Delphi) pumps are the only way to go with these trucks.

2. Get the computer scanned and check the codes. Could give some more insight to the problem.

It was an AC Delco pump. I went ahead earlier and replaced the coil, took out the spark plugs and cleaned them and it still wont crank. Just seems like it isnt firing. How can i check the computer? Thanks for your help!

It was an AC Delco pump. I went ahead earlier and replaced the coil, took out the spark plugs and cleaned them and it still wont crank. Just seems like it isnt firing. How can i check the computer? Thanks for your help!

What was o the plug?
Black stuff or fuel oil or dry carbon?

Does engine crank over good?
Is fuel pressure up to par?
Does it get good hot blue spark to all plugs?

On the computer check for codes first thing.
A good engine scanner will read out all sensors right if computer is working right.
Post back fuel pressure readings and if good spark and if cranking good and any codes.