G'day,
Last week, virtually out of nowhere my 04 Fairmont Ghia started chuffing / misfiring at idle and when just punting around. Its defiantly more then a coil pack or injector problem as its more then one cylinder as it came all of a sudden, so its unlikely (to me) that more then one injector / coil pack would go at the same time. The fuel pump, coil packs, ecu, map sensor and fuel filter have all been done recently (within last 15,000k's / year). The interesting thing is over 3500 revs it clears up and pulls like a train while at 1500 revs it is terrible. It also seems much worse once its warmed up. Im thinking something along the lines of a stuck cam phasor, o2 sensor ect, maybe crank sensor. I have scanned the ecu and nothing came up. The ignition timing was between 15 / 35* which seemed ok?

Any ideas would be appreciated. Ive searched online and haven't found much

Thanks,
Jay

check the intake manifold - spray wd40 or carb cleaner around each port its quite common for them to come loose and suck the gasket in, causing that exact issue