Nissan Repair: Sensors, nissan sentra, air control valve

Question
Hello Von,

I have a 2001 Nissan Sentra and recently had the "motor heads" replaced and the radiator, which cost me $1,150 for the whole job, After a couple of days my car started to shut down on me everytime i would park and shift on reverse, the "check engine" light went on and sometimes when im stopped on a red light. I took it to the same mechanic today and told me it was "a sensor", im not sure what kind of sensor he is talking about but he said it will cost me $100 to replace it. I have spent too much money on this car, and i want to know if there is anything i can do to get this done cheaper. thx!

Answer
Juan,

It is probably the idle air control valve or the throttle position switch.  This is just something that happens and you should not be upset.  The problem when you take a part an engine things do break.  Solid state means that things do not move and if they do not move they do not break.  However, when you disassemble things they have been cooked into place and when disturbed they tend to fail.  mechanics are careful.  But, things happen.  I have had things like this happen all the time.