I have a 1991 Subaru Legacy with 100,000+ miles on the engine. The car hestitates fairly bad from time to time. It almost seems like it may have a misfire. The check engine light will go on and off a few times. I went to a mechanic and he hooked it up to a computer. It didn't show anything. I have replaced plugs and wires, fuel filter, and air filter. I have added fuel injector cleaner into the tank, and even started using high test gasoline. Nothing seems to help that much. A lot of times, especially having to go up a mountain to get home, the car hesitates really bad. Last night we were going down the interstate and you could feel the car jerking. It would get better briefly, then get worse again. My wife did drive this car, then she got scared, so we swapped cars. I have been driving the subaru for about 2 months now.

I have thought about taking the car to Wal Mart and having the fuel injectors cleaned. I know that clogged fuel injectors can cause a lot of problems, like stalling, hesitation, rough idle, and so forth. Could a professional cleaning help? Any other suggestions would be welcome.

 

I'm curious as to what type of computer he hooked up this vehicle seeing OBDII systems did not come out till 95-96 year vehicles.

I would check your O2 sensors.

Google "how to retrieve OBDI codes".

The car will spit out a few flashing lights, in which you need to count to get the code.

 

Skip the high octane gas, for starters. Hi-test gas doesn't have any magical powers, contrary to what the oil company marketing people would like you to believe; it merely contains more anti-knock additives.

I don't think you have an injector problem; at this time of year water in the fuel could be a problem, tho, so I would give it a good dose of a fuel system drier (something specifically to remove water, such as "Heet").

I would check/replace all other routine maintenance items in addition to the plugs and wires you've already replaced. Fuel & air filters and if your engine has them, distributor cap & rotor.

Here's a link for reading your own trouble codes as Hot recommends:

http://www.troublecodes.net/Subaru/