I used some of the Gunk Carb Cleaner today to clear up my carburetor on my GSL and I also did the steam treatment per the FAQ's suggestion and it worked wonders; the idle cleared up and the engine cranked almost instantly. I left it for a bit to go to town and when I come back, the car is idling higher (at almost 1000 instead of 600-700) but the engine is shaking and the exhaust is giving small backfires constantly. Revving it higher clears up the shaking but I can still hear the constant intermittent exhaust backfire. What in blue blazes happened to this car in that short time frame?

 

The only time my car gives off constant backfires at idel, is when the choke is on and the engine is warm. So maybe something is choking your carb, like you dislodged some dirt while were cleaning it, and its clogging something...iunno.

 

I started it up today. The backfires seem to be gone but it still sounds like a lawnmower.