[Phast SVX]

Well i have reason to believe that you may have a slightly faulty EGR Vavle. Stands for Engine Gas Recirculation. It re-initiates unbert exhuast fumes back into the engine to control the rate of combustions. IF the vavle solenoid is stuck open, then the engine runs RICH...horribly so. This solenoid is oonly supose to be open on eve nhighway driving were it can tame out your milage. But it should have triggered a check engine light, so it may just be slightly fualty or i could be totally wrong. The vavle is like 80 and install wasnt too bad, but my dealership ordered the wrong part THREE times before getting it right. The correct valve a ssembly for my MY92 was 14774AA271 but check wiht subaruparts.com and your local dealer before ordering...i'd hate to somewhat be wrong and not have this be your problem at all. So take it to the delaer if your taht worried about it and ask them if they can troubleshoot it....tell them you think it might be an EGR solenoid.