Hi Mike,
Might put a pressure gauge on your fuel line and see what it is at
full speed. I'm betting zero as it may now not be able to keep with the
more gasoline your engine can burn with higher octane.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Mike Romain wrote:
>
> I just tried a tank of that Shell 91 octane super crap on a trip and my
> engine went insane!
>
> I don't know what is in it, but my manually set up 258 would 'not' run
> over 65 mph except on a down hill, I even had to gear down on a couple
> long uphill runs, which is unheard of for my rig, even 3rd gear wouldn't
> pass 65 mph! (normally 3rd pulls fast up to at least 75 mph)
>
> I also lost about 30% for gas mileage. It made for a long trip home
> too.
>
> I finally got it low enough and put in Esso gas and magically my engine
> came back alive with it's normal tire chirp off a fast start and top end
> power restored.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's