[RidgeRnr]

I have a 2004 S that backfires when I roll hard off the throttle, especially going down hill. If my calf is against the air box, I can feel the pop and it's about as loud as a 9mm. Otherwise, she runs fine.

Any thoughts as to the cause?

Mike
aka RidgeRnr

 

[Mr. Incredible]

aftermarket exhaust?


most aftermarket exhausts allow air into the system at the flange as they can't fully seat into the exhaust port and the acorn nuts bottom out. I installed some 3mm standoff spacers between the flange and the acorn nut to force the flange to fully seat without the acorn bottoming out,

got rid of about 95% of the decel pop, I still get a little pop sound now and again but sounds nothing like what it was.

Lyn-Tron, Aluminum, Metric, M6 Screw Size, 13 millimeters OD, 6.3 millimeters ID, 35 millimeters Length (Pack of 5): Hardware Spacers: Amazon.com: Industrial & Scientific

 

[Vinish]

If seating of the pipes into the exhaust port crush gaskets is your problem and if this is caused by bottoming out of acorn nuts, you can also just put several stainless steel washers under each acorn nut.

 

[Bohdan]

I had a vacumn line de-attached to the air cutoff. re-attached it It was good

 

[RidgeRnr]

aftermarket exhaust?


most aftermarket exhausts allow air into the system at the flange as they can't fully seat into the exhaust port and the acorn nuts bottom out. I installed some 3mm standoff spacers between the flange and the acorn nut to force the flange to fully seat without the acorn bottoming out,

got rid of about 95% of the decel pop, I still get a little pop sound now and again but sounds nothing like what it was.

Lyn-Tron, Aluminum, Metric, M6 Screw Size, 13 millimeters OD, 6.3 millimeters ID, 35 millimeters Length (Pack of 5): Hardware Spacers: Amazon.com: Industrial & Scientific

I'm running factory exhaust, no mods.