My Aveo is running with the check engine light on. I can drive it around but there is a loss of power. The loss is so much it is hard to drive. At first this problem made the car nearly undrivable. I had oil in the spark plugs so I changed; the cover seal, spark plugs, and wires. This helped with the power problem and I can drive it but there is still a loss of power. Additionally my MPG dropped to 24mpg. I have the following engine codes (Confirmed P0340 P0458 P0031 P0037 P0403 ) (Pending P0340 P0141 P0458 P0031 P0037 P0403). Changing the camshaft position sensor didn't resolve the codes. I took out my multi meter and found the mass inflow sensor and throttle position sensor have a 5v power input and resistance across the sensor.

Engine Codes
(Confirmed P0340 P0458 P0031 P0037 P0403 )
(Pending P0340 P0141 P0458 P0031 P0037 P0403)