spark plug won't stay tight
 

OK guys, this one is really stumping the heck out of me here. A while back I did a tune up on my truck (00 Blazer ZR2 4.3L) including plugs, wires, cap and rotor. Now a couple weeks ago I noticed the truck hesitating in the 1-2 shift. Trans was rebuilt (twice) very recently, so I can't say that's the problem.

I looked into it and the spark plug all the way in the front of the motor (closest to the radiator) on the drivers side was loose. As in, 3 or 4 threads from falling out.

I took it out and inspected it, all the threads looked fine so I double checked the gap and reinstalled it. Truck ran fine again for a few weeks, and now the other day it started hesitating again. And yet again, that plug was loose.

What in the world could cause this and how do I stop it from happening? Any ideas?

is it possible your using the wrong plugs ? sometimes plugs can be knocked out if there the wrong ones

Ive seen this happen before

if the plugs are a little longer then suppose to be they would come out slowly

Its the same plug as the other 5 and they're still tight?

this is just weird. Id change out the plug,maybe the threads are eff'd from the factory..

or better yet,switch a plug from the cylinder beside it..



I HOPE your threads in the head isnt bad...god that would suck.......

is it possible to rethread it ? I wonder

Good idea... I will have to swap the plug to another cylinder soon.

Eh i wouldnt think so. i doubt you can get sparkplugs that would fit the new bigger threads. even then he'd still have to pull the head. you wouldnt want to get shavings inside the cylinder..

Yeah if the threads on the head are bad I can just get a jy one to replace it with.

Yea,just be careful,apparently these vortec heads are bad for cracking etc. At least i was told that about the v8 vortecs. Not sure on these.

Well, let's hope it doesn't come to that. I'll swap that one with another cylinder soon (hopefully tomorrow) and let you guys know what happens.