So I've got a 2006 Chevy Trailblazer LS, 4.2 liter.

Right now, occasionally (but it seems to be getting worse), when I turn the key and try to start it, there's nothing. It doesn't
crank at all. I can roll the key back and do it a few times and so far it will then eventually crank and start. The dash lights
all come on, no flickering, not dying in traffic, nothing of those things like when the ignition switch is bad/going bad. I did
replace the ignition switch last year.

There's no slowdown when it does crank, it will then start right off. No warning/indicator lights are lit up on the dash.

Any ideas? Just as a guess I was leaning towards the key cylinder.

Thanks all, appreciated.

 

Original starter? If you have a helper, next time it happens, while key is held in start position, give the starter a gentle tap with a hammer. If it comes to life, time for a new starter

 

I replaced the starter last year. I really don't think that's it because it doesn't slow crank, or anything like that.

When you turn the key and nothing happens, you can roll it back and try again, sometimes a couple of times,
and it will (so far) then start.

Would a bad key cylinder do this? Thanks.

 

No, a bad key cylinder would not cause this. However, a bad ignition switch could cause this. The ignition key cylinder is a separate part from the ignition switch.

Here is a link to a how to replace the ignition switch:

https://www.trailvoy.com/threads/how...ch-pics.61278/

Good Luck!

 

I finally went ahead and replaced the ignition switch with a "Standard" brand from O'reilly.

This seems to have fixed the problem. Also, the "action" of this new switch is much, much
crisper than the old one.

Also, just for the fun of it, I did check the connections at the starter. I couldn't turn the main
12v line nut by hand but when I put a wrench on it (man, it's hard to reach!) I was able to
put 2-3 more turns on it. I had already replaced the ignition switch at this point so I guess
I'll never know if that had anything to do with it.

Oh well - it's fixed, regardless.

 

Thanks for letting us know you got it fixed!