speed sensor problem

[nadircicek]

hey guys, i have a problem which i have been suffering with for a long time...
here goes..

i drive a 94 2jzge non turbo i love my car as it is my first car :P got it cheap but there is a minor problem which is majorly getting on my nerves...

As i am driving, the revs will play around a bit.. when i start the car it will be on normal revs or higher (if the engine's cold) but then as i am driving and i stop at the lights for example, the idle will drop down to maybe '500' or even lower.. Sometimes it will even bounce of '0' or sometimes it just hits '0' and stalls altogether (while i am on neutral!!!). Also as i am maintaining a steady speed the CHECK and ENGINE light turn on and stay on for a long time... When this first happened i got scared but then as i have had many mechanics look at it they told me that the warning was harmless and had something to do with the idle problem.....

I AM IN DESPERATE NEED OF HELP AS I HAVE SPENT A LOT OF MONEY TO MECHANICS FOR THEM TO TRACE THE PROBLEM....

i have had mechanics delete the error code (which seems to be a speed sensor code) but it keeps coming back up... When i tell people it's a speed sensor fault, they ask me if my speedo works.. YES!! it works perfectly fine.. Recently i took it down to a mechanic who my friends say knows a lot about import cars.. now he said "the problem might be in the odometer" he took it out and had a look at it it seems okay but he says that the fault must be in that... He thinks that supra's most probably communicate the speed and such from the gearbox speed sensor and then instead of running to the SPEEDO, he thinks it might go to the ODOMETER instead. He reckons that if i replace the ODOMETER reading thing then the problem should be fixed..

Note: As i am driving down steep hills the idle seems to drop faster.

PLEASE PLEASE IF ANYONE KNOWS ANYTHING ABOUT THIS PROBLEM ALL FEEDBACK IS VERY VERY MUCH APPRECIATED....

THANK YOU....