Ok car is an 08 hhr with the 2.2 with about 200000 miles on it I just replaced timing chain balance chain and water pump all with new tensioners finished bolting it up and started the motor it is running and will start like normal but then goes to 1500 rpm before dropping to about 900 rpm with a stumble also after it runs for about a min I can hear a random what sound like back fire through the I believe the intake side l. Only code it currently shows is p0300 Did I blow this timing job or am I missing something stupid

 

You're probably off by a tooth. Did you replace all the guides?

 

I'm almost 100% sure the marks were all lined up and I don't hear any timing noise from a tensioner not activating also it will start like normal. Would it still do that being off a tooth? Thanks for the fast response

 

Which type tensioner? Did you whack it? Is the chain loose? Balance chain lined up?

 

Okay so after digging through the motor I found the line coming from the brake booster head broke off of somewhere does anyone know where that would connect. That kinda vacuum leak would cause all my problems I believe the brake booster side is fine just can't find where it should tie into

 

To the fitting on the intake manifold.

 

Ok so a new intake manifold is in store than that's kinda what I thought it tied to thanks for the help guys

 

I posted a pic while you were typing

 

I saw that thank you found the leak it's under the right side of the manifold below the last cylinder the spot that the pic shows is slightly different but mine is a panel version plugged the hole with my finger and she leveled off

 

You can look to see if you could tap the hole and screw in a pipe to hose fitting.