1998 suburban 3/4 ton wont start

Hi all I have a 1998 3/4 ton sub, one day I drove it to work after work it didnt start, a few hours later it did start a few days later same symptom, now it is parked in my house and wont start, It has spark, it cranks, sometimes I smell some gas coming out of the exhaust but i don't hear the pump, any of you guys have the same symptoms or something similar?? Please Help!!! this thing is driving me crazy.
thanx

just a thought but is it throtle body or regular fuel injection with 8 injectors? if its throtle bady you should be able to see fuel spraying in to enjine if not i would say fuel pump is gone or the fuse for the pump. try spaying a quick squirt of 1/2 second of starting fluid in the air intake. no more possibility of blowing a head gasket. if you get fire then i would say you need fuel pump.

Hi all I have a 1998 3/4 ton sub, one day I drove it to work after work it didnt start, a few hours later it did start a few days later same symptom, now it is parked in my house and wont start, It has spark, it cranks, sometimes I smell some gas coming out of the exhaust but i don't hear the pump, any of you guys have the same symptoms or something similar?? Please Help!!! this thing is driving me crazy.
thanx

This is the one with the 8 fuel injectors

I'd suggest getting a spark tester. You can pull a plug out and have spark under no compression, but it takes much more voltage for the arc to jump the same distance when you have hundreds of PSI present in the cylinder. Spark testers are pretty cheap... pretty much just a bolt inside a threaded plastic cover. If you can't find one, 30,000 volts is about 3/8" gap at atmospheric pressure. Yours should be quite a bit higher, but it would start and run off 30,000.

Also, have you checked the timing? The computer can get one false input (ie. crankshaft position sensor), and throw the ignition timing way off.

The engine needs 3 things to run:
Spark (at the right time)
Fuel (which you can smell in the tailpipe)
Compression (which you obviously have since it is/was intermittent)

Intermittent problems are (almost [I can't think of one that isn't]) always electrical, so I would look more closely at the ignition and computer inputs/outputs