Originally Posted by
rickair7777
Unless the POH says otherwise you should lean for taxi at all altitudes...this will keep the plugs from fouling in those engines that are prone to that. A long hold idling at full rich can foul them badly enough that a mechanic will have to remove and clean them.
haha rick is exactly right. this happened to us yesterday. I flew safety pilot for a kid yesterday and we went up to 5500 without leaning it out. When we got back on the ground, WOW the mags didn't like us. Thankfully we were with a mechanic and he got the spark plugs clean for us.