I have a 06 Lt and when i park and idle for a few minutes then rev it smokes only for a few seconds but lately the clouds are getting bigger. Its white smoke and it smells like burning oil. I've heard head gasket or the rings could need replaced. I will do the work myself but i don't know where to start . Also i have a bluetooth OBD2 reader and it keeps throwing a p0171 code. I have deleted the air intake resonater and i have replaced the muffler with a long style cherry bomber to give her a rumble. Any ideas ??