I found out that it was bad gas that caused my 2004 Monte Carlo to rev up while driving at constant speed on flat ground. But along the way I found the P1811 code which is the long shift I have experienced in going mainly from first to second and second to third gear. So I guess my transmission is going to go out eventually Can someone tell me how much a new tranny will cost?

 

You could just need the solenoids replaced, which isn't an awful job. Mix that with a pan drop and fluid/filter change and you could be good to go!