so, heres some background first. I drive a 2006 MC LTZ (3.9L). A few weeks ago, I noticed that i could feel a moderate vibration while sitting at idle. This vibration got worse if the car was in park. On top of that, my tach fluctuates VERY slightly while at idle. First off i replaced the plugs, because i figured they had probably never been changed since new (i was right, they were ready to fall apart). This didnt change anything, so i started looking for vacuum leaks in the hoses (carb cleaner method), again...nothing. So FINALLY i looked a little deeper and found a small rear head gasket leak. I plan on doing a top end rebuild at the end of next month and hopefully that fixes it.

NOW, to the newest issue!!

While accelerating from a stop at idle (foot not on accelerator) the car is very...jumpy well call it. I mean i can feel it pulsing forward every other second. This jumping seems to match up with the rough idle sequence.

My question is this, Can a head gasket leak, which is essentially also a vacuum leak, cause this rough idle and give the car that lurching sensation?

My guess is yes, but im no certified mechanic, just a driveway wrench turner

Id love to hear y'alls opinions on this, and sorry for the long post

 

Vacuum leaks cause weird things to happen, it wouldn't surprise me if those symptoms were caused by the head gasket. How many miles are on the car?

 

just over 110k, which really irks me because i have seen toyotas with over 160k that have never had the head gaskets changed, and still dont leak a drop of oil...

 

Eh, that is roughly time to change intake manifold gaskets, and unfortunately head gaskets in your case.

 

yeah that is just my luck though...fortunately i enjoy doing this kind of thing!