Engine Pop when I get on it.


1986 Buick Regal T-Type
I recently replaced the MAF in my Buick, ran it around nice and easy with 93 and went and picked up sup VP Raceing gas yesterday. I put 5 gallons in with less of a 1/4 tank of 93. It ran excelent, but I noticed when I got on it and about 4 seconds into it I heard a POP from the engine, almost like a backfire...I was like...possibly a lean pop or spark plug(s) going out. I ran race gas in it before the MAF went out and it didn't do this. It did the pop 2 more times then I never got on it again. I have Erics chip tuned for 93 with alky and running 22#. I know my 02 Sensor is out, I have another on the way also...any help is greatly appreciated. :D

EDIT: My car still runs excelent! The POP scares me though... :eek: