I have run 85% through an 83 Trans Am, 90 Chevy 1'2 ton, 88 Celebrity, and I know plenty of other people that have done the same, with the only trouble I never had, but he did, was vapor locking on a 91 Grand Am, which is throttle boby. Multiport type injection shouldn't cause any trouble that way. My experience was that they ran better on the ethanol, but I also always run 10%. If it can handle 10%, they can handle 85%, same problems will be present, concentration doesn't stop that. The computer will adjust according to emmissions signal and power needs. The T/A was carbed, too, but was the wondrous electric carb, and still runs fine today, in fact, all but the Celebrity are still roadworthy with no ill effects. The Celebrity got retired at about 300,000 due to wiring issues and rust belt cancer.