CHeck the level of your oil...you may have overfilled it that last oil change...how many quarts did you put in? I watched someone overfill his crankcase many many years ago and it reacted the same way. He just drained out the whole thing and refilled the appropriate amount and everything was all gravy. Driving around with too much oil is not good for your engine and may eventually end up causing a blown head gasket. But in this guy's case I was spectating, it was okay.....This oil level thingy is just an idea, you may look into it if you like...before shedding out more money having a compression and leakdown test done to see how you're burning the oil.