1995 Camry high Idle issue

I had all the major gaskets (6 I was told) replaced in my Camry last year( I bought it at Auction in April 05,, it was a one owner all highway driven car up till then) but my car still exhibits slow steady oil loss on driving, though never any leaks when its standing.... within the last few months it has been starting to idle higher than normal,,, on and off,,though now the idle is at least 2k pretty regular, i checked oil levels, they were/are normal. Suddenly yesterday,,, it attempted to jump from 2k rpm to 3k rpm while i was driving it(Im trying not to drive it at all right now) The engine feels and sounds smooth but the oil issue remains and now i am hearing the engine,, my friend got under it and thought he saw a hole in the muffler line, to explain the noise part,,,, any ideas before i show up at the repair place would be most helpful
1995 Toyota Camry; 4 cylinder; 249,000 miles; standard