John Speake

The 90mpg is a test of the closed throttle switch, so that is a good sign all is OK with it. It also means that the idle control loop will try to activate.

But you need to be sure it activates reliably, hot or cold. When the car is left the unhood temperature get very high. This may trigger an idle switch problem. The TPS has a design fault with fractured solder jopints that can make it intermittant. The fact that it clicks doesn't mean it is sending the correct signal to the ECUs.

See post #27 in this old thread https://rennlist.com/forums/928-foru...-switch-2.html

I am sure the same problem can occurr with thre closed switch parts as well as the WOT part.

You can send me the LH ECU for testing. It could prevent you spending unecessary money...