Should higher grade gas foul my system? on 1993 Saturn SC2

I switched up recently and topped off my SC2 with mid grade gas...and since then all heck has broken loose :( This is more of a project car, but has always been a decent running car. But after topping off the tank with about 5 gallons of mid grade gas versus the usual "cheap" gas, the next time I drove the car it started sputtering, hesitating, and would cut out once I put a load on the engine (it's a 5 speed). I replaced the PCV valve, new plugs, new air filter, thinking I had fixed it. WRONG!! It would start, idle for 10 minutes or so, then run very rough and eventually cut off entirely. So I'm thinking once the engine warms up is when the problem occurs. I'd let it set for about 10 minutes, crank it up again, same result. Almost like the old carb cars when they would flood out. I'm thinking it is something emission related, or a clogged fuel filter (the car now won't crank at all, turns over but never fires, making me think it's a fuel delivery problem). Any ideas PLEASE??

by in Charlotte, NC on May 14, 2009
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4 answers
ANSWER by , January 18, 2010
This car is designed to run on regular unleaded. The timing is set for the temperature at which it burns. Unless you have modified the computer with a programmer or "chipped it" I would recommend using regular. Your problem is most likely the idle air control valve. These symptoms resemble those caused by a faulty one. Try cleaning it or replacing it.
ANSWER by , May 14, 2009
The problem is not caused by use of mid grade as opposed to regular gas, all though you may have got bad gas or gas that is contaminated with water. It sounds like your car needs to be looked at by a garage with test equipment and service information on your car. A car needs mechanical integrity, (the ability to develop compression and the valves need to open and close at the right time, timing belt in synchronization....) It must have spark and fuel (correct fuel pressure and fuel delivery). If any of the sensors have failed MAP, crank angle, cam sensor or coolant temperature sensor failure will cause similar problems to what you are experiencing.
ANSWER by , October 05, 2011
My 94 SL2 had this problem, but not the same cause. I fixed it by patching a small vacuum leak on the valve cover, filling it with a couple gallons of 93 octane, and putting fuel injector cleaner in the tank, and spraying a bit of carb cleaner in the intake. Runs great now. That was about 2,000 miles ago. Every once in a while it was a little hard to start, I changed the fuel filter and the air filter, starts no problem.
ANSWER by , April 16, 2012
i got a 95 manual sc2 i run mid 89 octane and i have noticed that it dont burn as much oil try a bottle of z max worked for me