These past two days I've been experiencing a weird problem: when I'm at slow speed and starting to apply the break, the engine races and the car surges forward. The tachometer goes from about 1k to 2k, I also notice the TOD trying to engage. Everything goes back to normal after a short time.

What could it be? Is it a senor or something?

The only thing I can think of is that I put some cheap gasoline in the tank (i.e. not Mobil, Shell, etc...) About 15 gallons. Could this have something to do with it?

as always, thanks in advance.