Thanks. But since the intake manifold is plastic. I just used a 1/4 drive with the 10mm socket and went 1/2 turn past snug. I am hoping that this will work. I had 5,6 cylinder bolts really loose. it was causing a P0171 error. It would also stahl out went the temp. was below 20 degrees. Started it last night and this morning and seems to be pretty good. No error codes and not stahling out. I found it really hard to belief that the manifold bolts were so loose. This must be a defect from the factory. I spoke to a Service manager at a chevy dealer and he immediately said a commen problem is loose bolts on cylinders 5 and 6.
I'm also thinking that a guy should put some locktight on these bolts.
We will see how long it lasts, It lasted 147,000 miles so far.