This issue started this fall when the weather was cold & wet. My Trailblazer idles very rough, when I try to start it dies several times unless I keep my foot on the gas. After doing that it will sometimes stay started, but still idles roughly & usually dies once put into gear. Sometimes the check engine light is not on at all, other times its on & constant, & lastly it also will flash. I had ran a diagnostics on it & got a code of the cam shaft sensor. So I replaced it, next morning the problem was back. Did another diagnostics on it & got the crank shaft sensor so I again replaced that. Problem persisted I then was getting a random misfire code so I replaced all the 6 spark plugs. After all this I took it to a shop for a more thorough diagnostics, they determined there was a faulty wire to the fuse panel & replaced that. I did NOT have this problem all spring & summer, but now that the weather has turned cold again the problem is back and worse! I'm at my wits end with this problem. Does anyone have any ideas??

 

have you tried to clean the trottle body? a dirty one can cause this issue and trailblazers are famous for gunking up the intake