problems with 2001 toyota camry v4?

I have been having some trouble with my camry. I have never had to fill any coolant at all, and there is no leaks. I checked it last month before the problem occured and the radiator and overflow were full. I checked yesterday and the overflow was virtually empty. When I start the car instead of idling at 500 rpms, it revs and then idles at roughly 1200 rpms. The accelerator pedal is extremely touchy, but at the same time it will occassionally stick to the degree where I cannot push it. I tried checking the throttle body and it was clean as expected. I have 94k miles and I had a brand new, not salvaged engine, put in at 65k miles. I tried pulling the accelerator pedal in case it was sticking inwards and its out all the way. I use mid grade gas as per request of the delearship, and take care of all the regular maintenence on schedule.

Any ideas?

Thanks.