Hope someone can help or give me ideas of things to check. I have a 2004 santa fe 2.4 petrol. Its the 4 cylinder 16v engine. When warm the car has a major hesitation issue at 2000 rpm. Its as if it closes the throttle body for 2 to 3 seconds then re-opens. Its getting worse recently but doesnt seem to be related to external temps. Ive sat with a scanner plugged in and live readings off the o2 sensors seem to be in the normal range, the cats aren't blocked, Ive changed the coils and plugs and the throttlebody is nice and clean etc. Air filter is relatively new and the car has had injectorcleaner through it. None of which has helped or changed the issue. fuel filter is a cow to swap and in my opinion wouldnt cause the issue. Would a faulty air flow meter give these symptons or a dodgy knock sensor maybe? Even possibly the EGR system?