I am trying to fix my neighbor's '01 Lexus IS300 (3.0L I6 approx. 120,000 mi.) The problem started off as totally random, maybe once a month, but has progressed to a constant issue. It started off as a loss of power and throttle response. The check engine light came on (codes P1127 and P1600) and the throttle would only work in the last 30% of pedal travel. The motor would run fine, but only have the limited throttle. The problem over time then progressed to about the last 10% of pedal travel as usable acceleration. Finally the motor would not start one day, which is where I came in and got involved. I have replaced the camshaft position sensor, and have now found that the throttle cable pulley actually has a gap between where the pulley rests in a " closed" position, and where it actually contacts the tang on the throttle body rod. The throttle position sensor is at the other end of the rod, and works just fine, but where the pulley mounts to the throttle body is another position sensor of sorts (this sensor is the piece that contacts the throttle body rod). I have tried to adjust the tang on this sensor and had no luck. What could cause this problem to come up, then go away? It seems to me to be a mechanical issue, but how could that affect the CPS circuit? With the new cps installed, the P1600 code is still present.