Idle speed - my car idles too high for a few seconds when i stop before it drops back to normal, it also idles uneven, i took the plug off the airflow meter and it has stopped doing this, is the problem with the airflow meter or something else

With high idle in park, usually my first test is to block off mouth of throttle body. It should kill the engine, if no or very little effect on idle, You got false air getting in there from somewhere.
What about your cruise control? You can check and clean idle air system, where applicable? Any applicable trouble codes?
I don't know year--make--model?

could be one of a few reasons , get the OBD codes read , they will tell you which sensor/switch circuit is causing the issue

013 Idle Speed Problems PCM Test

007 Idle Speed Problems Scan Data for Idle

test don't guess .

There could be two problems i can think of here. First would be a computer problem. The computer might be telling the car to run at a high speed. A problem like this might be fixable from your local garage. A problem like this could be expensive. Second, as engines age, they natually tend to idle higher. This is a normal occurance. This is accompanied by a decrease of gas mileage. For me, i went from normal 26mpg down to around 22mpg. A problem like this can be fixed by using fuel additives aimed at high mileage cars. I have used fuel injector cleaners, and that has brought my car back to her glorydays of 1996. I hope this helps, if not let me know.

wet ecu

the ecu compartment is under the windshield on the passenger side on E36

you gain acess to it under the hood....
this compartment gets wet, the ecu lays on a flat surface in that
compartment.

the bottom side of the circuit board gets wet and starts corrosion.

remove the ecu, take the bottom plate off, clean the bottom of the circuit
board with alcohol and a soft tooth brush.

you should be able to see the signs of corrosion or conductive build up.

this gunk bridges solder points doing all sort s of wierd things to your
car, including false sensor readings from asc/abs controllers and other
sensors....

all the way to engine failure and worst case burnt and shorted wiring
harness.

I'm on my 3rd ecu, took me and the repair boys a few years to figure this
one out.

BTW: i would get that ecu mounted above that flat surface, use some sort
of standoff to raise it so that it is not laying in the wet.

you need to ride the car, for a few more miles until the ecu makes some kind of self diagnostics and reprograms idle speed control if it doesnt then you should go to a shop for a idle programming, its done with a scanner that lets you enter to the ecu's k.o.e.o test (key on engine off ) and k.o.e.r. test (key on engine running ) and there the ecu is going to ask for idle desired adjustments

YOUR ENGINE IS IDLING LOW.MOST CARS WHEN YOU TURN ON AC THE PCM WILL INCREASE IDLE SPEED TO KEEP ENGINE FROM STALLING OUT.I WOULD HAVE THE IDLE SPEED CONTROL CHECK OUT AT THE DEALERSHIP.THEY WOULD HAVE TO ADJUST YOUR IDLE SPEED.SINCE MOST IS PCM CONTROLLED.

Replace the idle speed control valve.Very common on fords this fails.And what you are telling me are the same symtoms.Good luck m8.

Here is the cause of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

The PCM controls idle speed to ensure good driveability. The PCM will only attempt to maintain the desired idle speed when it “knows” the throttle is closed. A throttle switch or the TPS input is used to determine when the throttle is in the idle position. Motors and solenoids are used by most PCM’s to control idle speed. Many PCM’s are programmed to attempt to control the idle speed by adjusting spark timing and then by controlling the idle speed actuator. Some computers of the early 80's did not control idle speed.