Just recently bought a 06 cobalt ss/sc with only 10500 miles on it From a chevy dealer here in town. Well started having some problems with it. first i noticed the other day when i pulled into my drive way and came to a stop and was at idle i heard a loud rattling and clanking sound coming from the motor i popped the hood and it sounded like it was coming from the vavle cover area the noise was there for about a minute then stop and sounded fine. Its done this about 3 or 4 times already in the past few days could this be the timing chain tensioner i know they had problems with these or would a bad tensioner do this all the time...and i also noticed while i was sitting in traffic the idle would jump and down then idle fine. So i took the car back to the dealer and explained the problems so they kept the car for few days to look at it. Well i get a call today saying the they can't find anything wrong with it that they can't get it to do any of those things. So i picked up the car today was driving it home and was on the highway and dropped it down to get around traffic and it stalled so i pulled over to the side of the road and it wouldn't start back up just kept cranking and would spit and sputter and then it finally started and was running fine. Got it to the house and hooked it up to my code scanner and got code po171 system to lean bank 1. I didn't see no cel come while i was driving or anything. Car is bone stock....Thanks

 

Check for exhaust leaks... Check downpipe n header...

 

Maybe ur dp had a small crack causing the rattle noise and when u got on it to get thru traffic , ur dp might have cracked more.. happened to me

 

Would that make the car stall? and not start for a few

 

Mine jjust went into reduced power mode..then stalled after a few mins...

 

Thanks i'll check that out tomorrow

 

maybe you should post this **** in the correct section its called problems and service

 

lol really!!!