What are the symptoms of bad gas? I have been driving my 87 350 tbi for about three months now with no problems at all. About 500 miles ago, I put on new plugs, wires, cap, fuel and air filters, etc...and everything has been fine. Today though, about three blocks from home, she started sputtering, the check engine light was going on at the low rpms, and ran like crap. Revved her to the moon, ran great for most of the rest of the day. Thought it was a minor hiccup, and then she did it again. This time I had to pull into a parking lot cause I thought I wasn't going to make it home. Decided to try and limp back, couple of blocks later, she cleared completely and ran great. What is going on??? Thanks for any input!