What grade of gas are you all putting in your Hummers? Do we have to put 93 or 92 octane gas or can we put 87 or 89?

 

Your OEM programmed PCM is set for 87. So unless you do a PCM tune, anything more than 87 is a waste of cabbage.

 

Doc is right, I would also add that I would recommend to buy from a top tier station such as Shell or others.

 

BUT isnt gas of today a worse diluted grade than it was back then and doesnt it also contain ethanol?

 

it is not a worse diluted grade. the ethanol serves a purpose. todays fuel has more detergents to keepengines i jectors and other fuel systems components cleaner. case in point. rip down an old engine like say an old carbeurated 350 they used to have a ridge of carbon at the top of the cylinder you would have to ream off to pull the pistons. in newer engines you dont see this problem as much due to detergents and higher refined cleaner fuel 87 has the same amount of detergents as the 93. for a piece of mind run a can of bg44k every oil change which is awesome ****. if u cant find bg44k use lucas fuel injector cleaner. all the others are ****ty snake oil bull****