Hi guys, My girlfriends car has developed an issue. It starts but the rpm slowly drops until it stalls. It can be kept up with the throttle. We've ID'd that it is running rich and missing when it begins to drop engine speed and have removed and cleaned the distributor and leads. We weren't able to take all the plugs out but the one we removed was fouled pretty bad with carbon. The missus noted that they changed the air filter last service and said that the filter looks different. It may have been replaced with stock. I think we might need to replace the filter after the plugs to a less restrictive filter to lean out the mixture a bit. However I don't know much about engines. Any opinions would be awesome!! Cheers.