1997 4.3 Vortec-Crank with No Start in Rain/Moisture
 

This has gone on for two years and over two grand. (Truck is a 1997 GMC Jimmy) I am slowly going insane. When it starts, it runs GREAT...but if it is moist outside, it is not going to happen...can crank it til the battery dies. It does everything but actually START.
I have replaced: spark plugs, fuel pump, MAF Sensor, distributor cap and rotor, stupid poppet fuel injection, battery x 2, and the ignition switch. It used to pull a random misfire code, but now has NO codes.
I have been through five garages and four really good at home mechanics. I've also read a ton in this wonderful forum (really thought the ignition switch was going to be the answer) When it is not starting, it has spark at the plugs and good fuel pressure.
Last mechanic wanted to do a second fuel pump with the new injection system...I swear I think it is because I am a girl...PLEASE help me. I love my truck, but I am running out of money to throw at it.

You could possibly have a vaccuum leak somewhere.

anyone checked the ignition control module

The ICM is on my short list. I think my next step is going to be spraying water on various things while it is running. When it wouldn't start Monday, I took it back to 'get a fuel pump' guy and he said it had spark at the coil, but wasn't getting spark at the plugs. He said there was water in the brand new distributor cap and that drying it out did not fix it. It started the next morning when it had stopped raining and he put it back in my driveway.

I decided to do the spark plug wires, because I hadn't before and notice that they say Packard on them and are numbered, making me thing perhaps it was time. I'd never done them. The driver's side went pretty well, aside from one broken clip. I will zip tie it. However, the passenger side, omg...there is a clip under a hose back by where you add oil. I cannot figure out how to get to this thing. I am ready to cut the old wires and zip tie the new ones. Does anyone have a better solution??? How do I get to that thing?????