Re: I'm worried
I use Speedway midrange and premium all the time and have no problems. You could have some bad gas or water in the tank from sitting. Add some gas line antifreeze and a bottle of gum-out. I have heard that a 1/2 quart of Seafoam in the gastank does wonders, but change the gas filter afterwards. Find a reputable garage who can change your oil and filter properly. Running the old filter (if it was new) with synthetic probably won't cause any problems because synthetic oil is 73% conventional oil anyway. But change both oil and filter next time. You may also want to change the air filters -- there are two, one on each side of the silver engine cover. The engine is the thingy in the front of the car.