It did it 3 times in a row last night....I'd get on it and she would run great until 5,500 and then a loud intake backfire and the service engine light would flash on and go back off. Its never done this before. The car still runs great and not missing at all when just driving around. I don't shift the car until 6,800 when racing. It is my 91 383 in the sig. I just got on it this morning and now it runs just fine....anyone have any ideas???

 

bad valve spring? is my first thought . otherwise i think it means your running to rich. is it just one pop? then runs on through it ? does it just pop and miss at that point?
mike

 

I think its only one loud pop...but as soon as it pops I let off of it. It sounds like a gun shot coming out of the intake. The A/F gauge shows that its not running too rich. The valve springs have less than 3,000 miles on them, but thats what I've been thinking it is.