on my 88 240 with 160,000 i have a fi problem. i cleaned the engine compartment with aerosol degreaser and a low pressure hose and now it has no fast idle at start up and the idle will suddenly rise(automatic trans) when in drive at lights. it seems to run ok at speed. even when warm the idle wanders a little strangely.

i checked the following using my Bentley manual as a guide:

AIRMASS METER:
heated wire(terminals #2 to #3)=2.9 ohms[specs 3.5-4.0 ohms]
idle mixture potentiometer(#2 to #6)=502 ohms[specs 0-1000 ohms]
i turned the idle mix screw and received 0-967 ohms at the above two terminals and then reset it back to 502 ohms(where it was when i started)[spec 0-1000]
i did the burn off test and had a sudden blip of voltage after shutting off the car after revving the motor(positive result.)

AIR CONTROL VALVE:
i felt for vibration but couldn't tell for sure because of normal motor vibration.
between the outer terminals=41.1 ohms[spec 40 ohms]
betweet top and middle=19.7 ohms[spec 20 ohms]
between bottom and middle=21.5 ohms[spec 20 ohms]
i also removed it and cleaned it according to the directions on this site. it was fairly clean inside and opens and closes completely when connected to a battery.

COOLANT TEMP SENSOR:
i cleaned the connections but it is so hard to reach i couldn't remove it to test. could this be the problem?

OXYGEN SENSOR:
on two wire connector across terminals cold= 4.2 ohms[spec 3 ohms]
same as above hot= 11.3 ohms[spec 13 ohms]
harness side black wire of two pin connector=continuity to ground[spec cont.]
same as above for yellow wire=13.61 volts[spec battery voltage]
i ran the engine with the meter connected to the single wire connection and ground and had a wandering voltage of very small amounts, around 76 millivolts, that sometimes went into the negative[spec .4-1 ohms]

THROTTLE SWITCH:
my switch clicks when the throttle is opened.
my wires are different from what the manual describes. they say to test #2 orange to ground for continuity at closed and an open circuit at all other positions. then to check #3 black white to ground to get open at everything except full throttle which should be continuity. my wires are #1 orange, #2black, #3 two blue white wires. i never got continuity it any position with any wire, but it is very hard to get the test leads in there. could this be it even though the car drives fine at speed?

the heat riser for the intake is gone and i didn't bother to test that valve because the hose just ends NEAR the manifold and i figured it didn't matter where its air was coming from. i cleaned the intake hose and other hoses and wiped out the throttle body while on the car. all electrical connections got an inspection and contact cleaner. all vacuum hoses seem passable.

the car also has a broken kick down cable, but as far as i understand it that wouldn't be the problem.

a friend who knows 240s suggested the air mass meter because of the symptoms. it is so expensive, and i think my tests show it ok, that i hesitate to replace it without being sure.

any responses to this tome i've written will be greatly appreciated. thanks!
BEAR