Phillips 66 is 100% gas. The ethanol is what is hurting the mileage. It's like putting water in whiskey!

 

Ive found my stocih point for 10% eth is around 14.47, whereas 100% gas is supposed to be 14.68, and 100% eth is around 9.

 

ok so i filled up in Montgomery at a station that i know has 100% gas and it has made no difference whatsoever... my gas mileage blows either way. i'm almost 100% positive that it is somewhere between the gas tank and the point where the fuel rail connects to the fuel line.

 

Hmmm i have an 04 yukon and used to get better mileage too, then noticed a drop, prob just putting miles on the engine.....Anyone know what to do if I cant get the spark plug wires off of the plugs? I bought a cheap boot puller, and im pulling hard as hell and no luck....

 

are you twisting as you pull?

 

Yea I am...I bought a cheap as "performance tools" boot puller that has no spring in the handle, so it just pliers basically....idk also the wires have been on there for 108k, idk if that is too too long to pull a boot off or not. Im twisting and pulling the boot with no luck.

Also there are metal heat shields, and I have tried pulling those too, not sure how they are connected to the boot

 

the metal heat shields will only come of after the boot has cleared the plug IIRC. if you can't get the wires off, then take some diagonal pliers and just cut them off. you need to replace them right about now anyway.