I have a 1988 GL10 AWD MPFI Turbo 5-speed.

 

What is the sensor on top on the thermostat housing?

 

It has a two wire connector on top and two ~1/2" OD lines running to the intake. What is this thing? The two lines have cracks in them and i think that might be where my intermittent idle rpm comes from??? Sometimes it idles at 700, sometimes 1100 and sometimes 2100. Ideas?

 

Thanks.

if it is what i am thinking about, its the aux. air valve. i think it gives you the high idle untill the engine gets to temp, then it closes, or something like that.

if it is what i am thinking about, its the aux. air valve. i think it gives you the high idle untill the engine gets to temp, then it closes, or something like that.

 

Precisely.

 

It needs to have good hoses connecting it to the Intake. it is in the presurized portion of the intake.

 

You can "test" it 2 ways.

 

First, check that there is 12v between those 2 wires with the key on.

 

then, if you unscrew the valve from the T-stat housing, you can watch the vavle close. Leave the valve connected to the wires, and with the key on the elemnet inside should heat up and the valve should close.