TokyoDrift99
12-16-2014, 09:08 PM
Hello all, I have a 99 OBW 2.5 5 speed manual. My car intermittently throws a P0507 (Idle Air Control System RPM Higher Than Expected). One day the light is on others its off. I've had the car for 2 months and there is evidence the car sat before I purchased it. The used dealer I bought it from replaced both headgaskets, water pump, timing belt, and alternator. I have noticed that the car is painfully hesitant upon acceleration. If I am cruising anywhere between 2000-3500 rpm, and floor the car it barely speeds up, gradually it will build power. This problem is very relevant on the freeway, and on on ramps to get on the free way. The car has ZERO passing power. This problem screamed vacuum leak to me, especially because sometimes pumping the brake pedal at idle can cause the revs to increase by a hundred or so. But after doing some research I have found that the neutral switch could be the issue, TPS, IACV, and MAF sensor could be fubar. About that MAF sensor... The pigtail is broken, well not really. It isn't cracked, but it doesn't click and lock in place. If I start the car with the pigtail pulled off a bit (to cause a bad connection) the car will crank more than it should to start (warm engine) and when I pump the brake pedal the revs shoot way up, about 1k or so higher. If i plug the sensor all the way in the car dies instantly. Plugged all the way in it will start instantly and only fluctuate a bit when I pump the brakes. Auto zone didn't have the pigtail and said it must be a part I have to get from Subaru. I thought the PCV may be malfunctioning so I took it off and sprayed some brake cleaner thru it (yes it rattles). I also used one of those screw clamp type hose clamps instead of the wire one because the line wasn't very secure. Still no difference. I sprayed brake clean on every vacuum line I could find, but found no leaks. I have a brand new air filter, and the only thing I can think to do is clean the MAF. Ill replace the pigtail when I get it from the dealership. Any ideas?