Bone stock 1992 Mustang, check engine light intermittent, mainly on with foot on the gas, light accel or cruise, off when coasting with foot off the gas. Three codes came up, 31, 91, and 95. Replaced O2 sensors, code 91 went away. Just 31 and 95 left. The scanner book and different online sources have conflicting information about the 95, with either a Fuel pump circuit problem or thermactor air diverter circuit problem, while 31 says canister or EGR valve control system. Neither gives much insight as to what might be the bad part. The car does have a fuel pump cutoff switch for an anti-theft measure, but the fuel pump runs fine and the car operates normally.

So far, I've replaced the EGR valve, EGR position sensor, and EGR vacuum solenoid with known good, low mile takeoff parts from my stash - no changes in that 31 code.

Thanks for any ideas!