Hi Guys.

I have had my FG XR6T Tuned in Perth a while ago with ID1000 injectors. I have noticed an odd idle best described as a rumble felt in the floorpan in my foot every few power strokes, it happens more so when you hold the engine about 100rpm above idle, so 700rpm instead of 600rpm or whatever the idle speed is.

I have not been able to get this tuner to check the tune due to them always not calling me back when I ring them and what not.
I managed to get some time with them for them to put a scan tool on, they said my fuel trims are off which means I most likely have a intake leak, or an exhaust leak causing the oxygen sensor to try to correct the mixture and cause this idle. So here I am now checking for leaks on idle spraying carb cleaner above and from under the manifold, in all PCV fittings etc, around all injector o-rings and have tightened all the nuts.

I took their advice and took all the heatshields off the exhaust and there is no signs of exhaust manifold gasket leak no carbon trace anywhere from headers to turbo to anywhere pre 1st oxygen sensor.

Does anybody have any more advice on what could be causing this. I will also say when cold there is a lot of unburnt fuel popping after a small rev in the exhaust. Spark plugs look good. The car has done 20,000km

Thanks.