Hi there

When car is cold, my revs are perfect but when the car reaches normal opearting temp , the revs drop to like 550rpm.

 

What gives???

Thanks

Revs will be higher when cold...its part of the "on choke" cold start running mode.

 

However sound like your base idle (and subsequently the TPS too) needs adjusting, which is why it sits at 550rpm and not 750-850 rpm when warm.

I have checked the TPS and its fine. I have also tried to adjust the base idle but the screw wont turn anymore and I cant seem to get the revs high enough.

 

??

You need to turn your base idle up. Zeds when cold should idle at a little over 1,000rpm until, and slowly drop as engine warms. Are you sure you are turning the idle control screw the correct way? If you still have no luck... remove the IACV, take it apart and clean it.