I have an old Toyota Previa automatic; it's done about 130k miles.
I recently tried to overtake, so floored the accelerator and pulled out; there was a lack of power and some very white smoke from the exhaust. I pulled back in and kept on my journey. This was during a longish trip and no other symptoms for the rest of the trip, although it didn't floor the accelerator again.
Again on another occasion I was joining a fast road so accelerated hard to get up to speed and the engine coughed a bit and looking behind I could see nothing except a thick white cloud of smoke blocking all lanes of the road. Coming off the power and the smoke cleared without any other obvious problems.
I have since checked the oil and water and neither seem contaminated, the oil filler cap opening does not have the sludge of a blown gasket, just clean oil. If I keep the revs 'normal' everything seems OK, it seems it's only when try to accelerate hard that I get the problem. When in neutral, revving the engine hard does not seem to create much smoke either.
Is there another explanation except a blown gasket? could it be linked to the automatic transmission?
Priority Action Part Type Cause
1 Inspect PISTON RING SET Worn or broken piston rings.
2 Inspect VALVE STEM SEAL Cracked or brittle valve stem
seals allowing oil to enter combustion chamber.
4 Inspect FUEL INJECTOR Rich injector
5 Inspect PCV VALVE Plugged or damaged pcv valve.
6 Inspect ENGINE Worn or scored cylinder block
7 Inspect PISTON Worn or damaged piston.
8 Inspect VALVE GUIDE Worn valve guides
Hope this helps.