Ignition switch might not be making all of the connections consistently. Need a DVOM or test light to check each circuit. Not going to be fun locating the problem, especially if it's not acting up at the time you test it. Intermittent electrical issues are THE worst!


Vapor lock is not possible on this system. The fuel is circulating whenever the pump runs. When the pump initially activates, it bleeds any and all air to the tank side of the fuel pressure regulator valve plate. This might take a few seconds if the system was opened, or has a leakdown problem.

 

You can always buy a cheap Chinese ignition switch. It won't be the quality of an OEM one, but for $25-35 bucks, it can give you peace of mind.


I just replaced my ignition switch. Mine would start fine, but every once in a while I would get a bunch of transmission codes and the truck would default to limp mode. Wouldn't happen every time I drove it, which was irritating. Swapped the ignition switch a couple weeks ago and haven't had a code since and the Blazer is running great.

 

I didn't get around to messing with it yesterday unfortunately so I'll have to wait till Monday to dap anything now. I thought about just tossing an ignition switch in and see what happens. Worst thing is of it doesn't fix it u pull it out and return it I suppose.