I have a 2005 Taurus SE w/ 3.0 liter V6 with 68,000 miles. Within the last week, I have developed several issues. The CEL goes on for a day or two then it will go off. I took to AutoZone and it show a 300 Code, which they said was basically a misc. misfire or malfunction. They also told me it could be one of a LOT of different problems. When I first start up the vehicle, my RPM used to start out about 1400-1500 RPM. Now is between 2200-2500 RPM, then it takes a long time to drop down, sometimes too low around 500-600 RPM, almost to a point where it feels as though it will stall. Once the engine is warm the idle is rough and the RPM gauge fluctuates between about 700-850 without the compressor running. Also, when I drive down the street at a steady rate, the car is surging a bit and the RPMs are not steady. On the freeway going about 60 mph, the RPM use to be about 2000. Now it is between 2200-2300. I'm disabled and unable to afford to take to FORD(charge $80 to put on computer). Any suggestions of something I could do to rectify my situation.