gti mk2 91

[Jmac]

Guys lets not get confused with backfire and afterfire. Backfire is generally in the engine and manifolds and afterfire is in the exhaust. Where is your back fire/afterfire ? If your exhaust has a leak any unburnt fuel in the exahust will ignite hence the bang. This fuel is ignited by heat and the o2 entering the exhaust. Usually a over rich system will do that. If the engine is backfiring then you may be running lean, vac leak manifols leak or yes the K/N. I had a KN cone on mine and a chip was ok . Without the chip your Air/fuel ratio is out of whack. Pull off the vac pipe on the fuel pressure reg and blank the pipe off and run the car and try. This will tell you she is lean mate.
Cheers

[dubsweeper]

yeah will go back to the other filter and put the inside thingys back in the air box as you said it is a bosch afm and looks like its been taken off ! anyways im going up bush for a few weeks and leaving it with a mechanicand they can put a stainless exhaust on and do other mods and come back for a surprise (early krismas)