For test drive engine was cold, truck ran great. Got home servicing truck noticed waste gate linkage was unhooked and small oil leak. Hooked up waste gate linkage oil leak stopped and know on a 80 degree day truck has to warm up a good 10 mins before it will run right. If you try to drive it before its ready, heavy black smoke and nothing more than 1st gear and 10-15 mph. Until it is good and warmed up and then its like you flipped the switch and off it goes like it should no problem as long as it stays warm. Confused, any suggestions?