1999 GMC Sierra wont start

[kboomisme]

Hi guys, I am new to the forum. My father in law has a 99 Sierra. He started having problems with it starting when it rained. Now it wont start at all. We have checked the fuel pressure and that is fine. We have changed cap, rotor, plugs, wires, and the ignition control module. It cranks but wont start. When you let off the key, it sputters a bit for a couple seconds and acts like it wants to run but wont. Also it smells gassy which makes me think it must be getting fuel. Starting fluid does not work either. Does anyone have any ideas on what I should try next. Truck has the V6, automatic, 4x4, 88k miles, Thanks

[oldscsc]

The two most common causes of no starts are either a lack of or improper spark or fuel.

 

Spark--I see you've replaced most ignition system components. Have you tested the spark?

 

Fuel--Just because you smell gas doesn't necessarily mean the engine is being properly fueled. Have you tested fuel pressure at the schrader valve on the fuel rail?

[kboomisme]

Yes, we had a neighbor test the fuel pressure and it was fine. We haven't checked for spark. Its weird that when you let off the key, it tries to run for a few seconds.

[kboomisme]

I guess no one knows??

[00Silverado4x4]

What was the actual fuel pressure reading? Also is the engine timing been verified? When you replaced the cap and rotor was everything tightened down straight? Caps can be cocked off to one side and cause all kinds of grief.