Yah, but mostly with lower grade fuel, you'll get a lot of knocking and pinging. As painful as it is, I use super and every other month or so, will throw in a bottle of fuel inj cleaner to help blow out any crap. Try a fuel system cleaner, chances are if only lower grade fuel was ran, the valves are a little gunked up...start small, little things, I'm not sure if a local store still sells them but, there's a wire resistance tool that MAC tools used to carry on their trucks, it looked like a small old transistor radio, the antenna would pull out and at the end was a u shaped hook that you'd slip over any part of the spark plug wire, if the resistance was high, you had a bad wire and so forth...