Does anyone associate the use of 10% Ethanol gasoline and rough idling? I just recently had idle issues and had the power valve replaced and a vacuum leak. I had those issues fixed and today it rough idled again. I sprayed some carb cleaner in the carb and the rough idle went away...I am wondering has anyone else had issues with varnishing or build up. I know these engines are not made for ethanol but ethanol free is few and far between. I didnt know if I just need to start using exclusively ethanol free gas unless im in a pinch.

Thanks

 

I used E-85 in my f100 and it ate all the seals up in my carb and ate up the rubber fuel line! Ethanol is some horrible stuff. When I used it I got 10 mpg and when I switched back to normal gasoline I got 16 mpg.

 

You used E85 in your dent!?!?!?!?! Please tell me this is a typo! Using that much ethanol would certainly require rejetting the carb and changing out all fuel system components to those that are ethanol friendly. I'm surprised it even ran!


To answer the OP, I haven't run into a problem, although some trucks are pickier than others.

 

10% ethanol will not cause rough idle. What does the vacuum gauge say?