I recently purchased my second Subaru, and it has some puzzling problems. When I start it up, it revs up to 1,500 - 2,000 rpm for 30 seconds and then drops down to 1,200. The AT Temp light flashes 16 times, and the Check Engine light is on. When I shift the transmission into gear and try to drive, it acts like the engine is under a very heavy load. At first, I thought the exhaust was clogged, but after checking, I don't think it is. As the car accelerates, it shifts very hard, and when I take my foot off the gas, the car slows down as if it had a stuck brake cylinder (but it doesn't). Finally, when I stop and shift to neutral or park, the engine still acts like it is under load. When I shut the engine off, the drivetrain relaxes, and the car rolls backwards a little bit. When I pull the code from the ECU, it tells me there is a problem with the idle air control valve. I took it off and cleaned it. I also tested the resistance on the pins, and they are around 9 ohms like they should be.
Could my idle air control valve still be bad?
What about this transmission problem? At first, I thought it might be the Duty C solenoid or transfer clutch, but I cannot read an error code from the transmission. I am using an ELM327 code reader.