Hi,

I have a problem with the idle of my 85 GL Vanagon.

When I start it cold, it start willingly and settle to a very regular fast
idle.

When the temp needle begin to move, the engine slows a little bit and begin
to idle very roughly.  Never dies though.  Step on the gas and it revs right
up with no misses or backfire.  When I lift my foot from the gas pedal the
idle isn't going back as slow as it should.  Runs very well on highway with
gas milleag around 25 mpg at 65 mph.  Horrible figures though in town due to
this FAST idle thing.

Here is what I did and adjust.

Full tune-up (cap, rotor, plugs, plug wires, timming set to 5 ATDC, air
filter, fuel filter)
The gas cable isn't sticky nor very old.
Throttle valve switch adusted as per Bentley (design with one switch)
New electrical connector to the AFM
No vaccuum leaks
Idle srew all the way in.
No difference in idle with idle stabilizer in or out
Complete new and tight exhaust system
New O2 sensor
All visible engine compartment ground cleaned

I have access to the CO adusting plug on the AFM, I guess a previous owner
removed the sealing cap.  The adusting plug is way in the hole, Bentley
suggest that the plug should be flush with the top of the AFM.  Since the
Vanagon is running fine except for the idle thing I didn't touched it yet.

Someone suggested the temp sending unit, the one that gives info to the
computer.

The van has about 110 000 miles.

Any ideas ?

Thanks in advance !

Ignace

1967 Volvo 144S
1985 Vanagon GL
1989 Mazda B2200 ($ 300 junk hauler)