I have an 89 tracker with TBI and the injector is pretty noisy.  Does this mean it is going bad or do they typically make noise.  I have noticed that newer trackers 90 and up don't seem to make as much noise.  Should I be on the safe side and replace it?  I'm not having any performance issues it seems to run good and I get good gas mileage.

Fuel injectors do make a fair bit of noise and usually more as they get bigger.  As long as the mileage is decent and she is running smoothly I wouldnt worry too much, but it wouldnt hurt to run some quality injector cleaner through the fuel system.

Thanks!  I'm going to run a test tomorrow and see if it's the injector or the ISC valve.  I would much rather pay to have the injector cleaned than try to find a replacement ISC. 

Whatever you do, don't hit it with 12v to see if it clicks.  That trick only works on the multi-port injectors, with the TBI setup it will just burn out your injector.