Hi, I have a question a couple of monts ago in had a shop do a custom catback with a mangaflow street series muffler . It sounds great not loud at all kinda of a hummmmm sound and really opens up when you get on it . anyways that is not my problem I notice when i shift from 1st to 2nd that slight pause when you push the clutch in it backfires from 1st-4th and crusing on the highway it will backfire .so I had a friend follow me on the street and he said that between shifts he would see small flames shoot out. he said that it did not do it all the time. I am worried is that normal or something I need to look into also I do have a jdm f22b sohc vtec (I know the engine cam with the car ) can you guys help me out thanks

 

Your running rich. It's just unburnt fuel combusting in the exhuast. It's not necessarily bad, but leaning it out will give a slight performance boost. If I remember correctly, when you run rich your timing retards and you lose some ponies. I wouldn't call it normal, but still needs to be fixed.

 

did they leave in your catalyic converter? if not then flames will come out, but if its just small flames, then i believe wat total is saying is true