Just done a search for P1507 and only got 4 hits so here goes car starts normally from cold, normal fast idle then after warm up period idle speed drops as normal but to about 1100 rpm instead of its usual 700ish, at this point the CEL comes on and code P1507, sometimes there is a high idle speed detected message but the engine rpm signal is correct at about 1100 rpm which agrees with the car tacho.
There is an occasional slight surge in rpm when idling which is sometimes regular then clears for a bit then starts again often when the cooling fan kicks in.
I'll try taking the IACS unit off tomorrow and give it a squirt of magic spray, I unplugged the IACS valve and nothing happened, idle speed stayed the same and engine would rev the same as with it connected so I'm guessing that's the problem?
Any other suggestions?
Thanks
Graham