According to the shop manual, the air pump magnetic clutch is supposed to stay engaged up to 3250 RPM. After the car is warm and idling, when I give a small amount of throttle very slowly (~1100 RPM), the air pump clutch will disengage for a second or so and then re-engage. I checked the air pump relay and it is OK (ohmed it out and I can feel the relay change states when I apply the light throttle). It seems that the engine computer is doing something in response to this light throttle to turn off (desengage) the air pump clutch.

Any ideas?

Thanks - Tom

 

you might try checking the TPS, the older rx's use the tps for a similar function.

you should be able to hold maybe 2000-3000rpms and the air pump should be on, i think.

 

How are you able to determine that it is engaging on amd off?

 

Visually while moving the throttle next tot he throttle body. It's very obvous to see since the outer piece stops rotating. Also did the same thing with my finger on the air pump relay and can feel the relay switch (which implies that the ECU is commanding it to do so).