1998 LS 4.3 blazer will start and shut off.Fuel pump is running then shutting off as it should engine will fire up and then shut down,seems to bee shutting off injectors, has also started random horn blowing with switch in off position,have reset security system by leaving switch on 15 minutes and turning off removing key then trying to start, fuel pump is approx a year old ,new fuel filter help started cutting off in damp weather, horn stared problem in wet weather also

 

Can't say for sure, but this sounds like it could be an ignition switch issue. I've read similar threads on what you describe. I would use the search feature and look for ignition switch and also read the "Tech articles" in the forum. Please come back and let us know more or what you did to fix it.

 

I am leaning toward this also , i am a motorcycle mechanic an dont have time to work on my own stuff! lol as soon as i get it i will let everuone know thanx