Engine Rattle / Chatter?

My engine chatters like a diesel.  Especially in the 2500-3000 rpm range.  It seems to be getting more prominent (can now hear it over the radio at conversation volume).  It also chatters when idling (I’ve been asked if my truck is a diesel 3 times now).  The power seems to be there and there are no engine lights but at 15k miles I wanted to get it resolved before it becomes a major issue.  I’ve looked around here and have only found one thread but it seemed to fizzle out.  I tried using different grades and brands of gas (ran Mobil premium for 6 months and now mostly Mobil regular) resetting the computer, etc.  It’s very consistent regardless of gas.   I’ve got the truck going to the shop for a transmission issue as well but wanted to know if this sounds like its unusual or maybe the engine is just “chattery” in the H3.  My friends Canyon doesn’t sounds like this at all.

Doesn't sound too good.  Mash the OnStar button when it does it and ask OnStar what engine diagnostic code they're getting (if any).  Don't have OnStar? Too Bad!

I tried that, there is not code (that they can read).  When i had a low tire light, OnStar could not tell me which tire, when my batter was no longer charging, they had no info on the charging voltage (and we have no guage).  I have found that OnStar is good for taking my credit card info and not much else.  I will throw it on the code reader when i get home just in case.

Ah ha!  Yep, I don't need no stinkin Onstar..................neither!!!!!

Folks, I have what sounds like the same rattle/chatter going on when accellerating.  It sounds like the same range of RPM and I was thinking that it was a loose skid plate or something.  Will check this weekend.  My 07 H3 was purchased last October and I have about 14K miles so far.  Will let you know if I find anything and report what they say next time I take it in.
 
Regards,
 
Jeff

Get it to the dealer! Or you could trade it for a 5.3 and the piston slap noise. Wait that might be what it is. If it is PS good luck getting it fixed. GM doesn't recognise the problem. Oh ya, and onstar sucks. Might be good if you robbed a bank and need a get away route.

Its going in on Monday.  I read up on the piston slap issue with GM engines and it does sounds like the clips, but its impossible to tell for sure through the internet.  I do feel its not normal and if there is an easy fix, that'll be great, if not I'll make sure the dealer fixes it.  I'll post the results.

If it turns out to be piston slap, it's not the end of the world. It is annoying but I've seen engines with PS and 140K miles on them. It seems to be worse when it's cold. My 5.3L would do it when you first started it or when it was really cold. Synthetic oil seems to help, but deffinatly not a cure.

i would try changing to synthetic.just to see if it helps

My I-5 sounds like post oil change start up every morning.  It clatters like the the lifters are bone dry for about 2 seconds then it goes away for the rest of the day.  I use synthetic oil just in case but it still does it.  It's annoying.

Maybe i'm just hearing RealJeep's early startup clatter along with balance shaft rattle and tieing it all together.  My 4.3l S-10  had wonderful balance shaft rattle and it does kinda sound the same.  Maybe changing to synthetic is in order (was considering it anyway).  I'll still let the dealer take a stab at it.  My transmission issue is my primary concern.

Thanks for all of the info!  Forums rock, everytime i get a new car its like joining a new family.