Mark, Answers below.. there is a coolant Y pipe 102147 under the intake manifold that has these parts in it 102478 lambda sensor and 102405 therm vac switch. since i will be in this area how do i know if these two parts are bad (102478 and 102405)? what do they do? should i replace. ( If the car is running properly, then I wouldn't replace sensors But, I would take them out and clean the exposed ends to the water and use Teflon tape to replace them.) Also the thermotime switch 102125 what does it do? should i also replace this too? ( Since the thermal time switch doesn't go out very often, then I would do the same thing. Clean the exposed ends and re use.) thank you Mark, One other thing I would do. I would replace the green air vac switch in the internal water pipe. It's the one on the left side of the internal water pipe. Being that it is mechanical, if it doesn't move internally to re direct the vacuum, you could have advance problems. It's a moving part where the others are not. John Hervey www.specialTauto.com VIN# 6683 >>