It will run fine at normal temp, then i'll get on the freeway or go up a hill and it will just go crazy with white smoke...its very random and never happens at the same speed, place, rpm, or temp...it is coolant, right?
After a lot of scratching my head and staring at my baby...Im pretty sure its a cracked or warped head.
Aftermarket headers were put on it recently (will never go there again). The power steering line rubbed up against the drivers side header and eventually burned a hole-- caused a fire underneath :ah: . I was able to get most out with an extinguisher, but then hit it with water as it kept coming back...the VERY hot then cold could crack or warp a head, right?
Might want to do a compression test. I can't believe the "mechanic" hasn't done that already, as that smoke looks nothing like thick burning oil (to me, could be a camera issue too).
Draining your oil/coolant is another way to check and see if there is crossover, but on this car both things will wind up running you over $100-150 in parts & labor. A simple compression test should tell you whether or not coolant is entering the combustion chamber through a bad head gasket or cracked head (won't tell u which), and it's cheap and easy to do.