Hey all, My car (99 hyundai excel twincam) splutters and coughs and the check engine light comes on only when my car is kept round 3 or less thousand RPM's for too long (usually when below 80km/h). If i thrash the car, its fine but when i ease off for too long just cruisin, then it splutters again! I changed the fuel filter last week and it was clogged up somethin shockin, i thought the clogged filter was the cause but i guess not :S! All the fluid levels are good and the spark plugs are fine (just checked everything) the spark plug leads are 1 month old top gun spark plug leads and on a long trip i had today (2 hours) the car ran fine at about 100km/h and 3000ish RPM the whole way. when i got back into the city it started this **** again! please help guys, i have no idea whats causing it!!!!