SES light (service engine soon )

[Buick City]

On my 90 vert the engine light came on,and I am leaving on a 4,000 mile trip,and didn't want to look at that all the way ! I looked at the cam sensor magnet,as I had that problem before with other Reattas ! It was there ,but loose,and had been rubbing the sensor.I put on a new magnet! The light was still on ,so I checked the codes . I had a E034 code ( maf sensor ) I checked it per the shop manual IN THE 90 MANUAL page 8D1-44   &  89 MANUAL  page 8D1-46  THE DIAGRAM IS REVERSED ! If u check volts between A and ground according to the manual , u get 12 volts ( should be 4 - 6 . The manual shows the sensor terminals (left to rt. CBA ) should be ABC ) When checked this way I got 5 volts ! I tried another good sensor ,and the light went out , engine ran better! The car had a new sensor on it when I bought it,but when I looked at it the filaments on the back they were blue They should be black,like they had been used ! I don't know what a new one looks like as I haven't bought one before ! I am glad I found the problem! LIGHT OUT !