Just staring to think things were fine, most jobs done (just radiator to do) and a nice polish at the weekend, then today coming into work, idling is producing yo-yo revs. When I come to stop, the car stalls.
Happened a few weeks back and resetting throttle position sensor cured it , but this didn't work today.
TPS?, IACV,? something more sinister.........
Never rains...........(well actually it does...frequently)
Iac valve is usually a good starting point. Pull the hose off and try squirting some carb cleaner into the valve.
I found you could do this via the access panel in the boot. If it improves, then you can get the old engine access panel off and do the job properly.
After cleaning and then replacing my IACV, I also found that the tickover adjustment was critical too, someone, could have been me, had altered the screw to try to remedy the yoyoing and this incorrect setting worked against the iacv causing the up and down effect.
I sorted this by, with a hot engine, watching the revs return to tickover.
I saw that the revs were dropping below 700 before returning to 850.
I gradually altered the screw until the revs returned smoothly to 850 without dipping below or hanging above. Reset the TPS after this and the revs have been almost perfectly behaved since!