1990 405

i am working on 90 model 205, upon start-up idle goes to 2500 rpm, i can take the idle motor out of the loop and idle drops to 900.i suspected the idle motor needed cleaning so i did so.it makes no difference,same results.The occurance of this problem does not matter if engine is cold or up to temp.
Can anyone point me in the right dirrection?

And can't help you unfortunately, but maybe someone else on the forum...

Do you have some pics of your 405 ? Have you bought this car new or in second hand ?

i am trying to repair for a friend