Anyone bother to find out why? is the O2 sensor any good? Temp. senors, fuel pressures, etc. I know it's after the fact but think about it... why would you have to adjust the fuel mixture? Unless someone messed w/ it before? It should not change correct? Now when you find the problem the fuel mixture will have to be readjusted. I would suggest starting w/ most common reason which is the O2 sensor on high milage cars.
Hydrocarbons is unburned gas, either an ignition miss or the mixture is to lean from adjustment, vaccum leak, incorrect mixture inputs from sensors, bad valve(s).
So your kind of all over the place, so it might be worth it too you to find a good Bosch injection mechanic, the KE system is really not that diffucult to troubleshoot for a good mechanic. Besides if your running lean your really hurting the motor.
Not much help, sorry,