It missed real bad then seemed to clear up. I had just bought a tank of gas at a small gas station here in ky, shell wasnt close by. I usually get theres and 93 octane.
The problem seemed to start after I bought the gas.
So I ran the tank to half empty and went to shell on my way home and bought some 93 and put a bottle of 103 octane boost in the tank. It seemed to get better the more i drove it. The stumbling and miss dissappeared but it still trips the p0303 code.
Do you think it was the gas or is it something that will get worse?
My mustang has 36k on it. So its pretty much low miles. I put new ngk plugs in it last year and it has a bbk cold air, throttle body and plenum.
Any insight is much appreciated