Have the TPSensor and MAF checked. The only reason I say this is because this is what happened to me: Going up a hill - CEL, try to pass someone - car boggs down and doesn't want to go anywhere - CEL.
'95 Contour GL, zetec mtx, drop in K&N, exhaust res removed, 4 10" Kenwoods powered by 1000W Visonik amp, 4 5"x7"/6"x8" Visoniks