My car is 82 380 SEL. lately its been giving me a headache. The idle on the car is perfect, rock steady when the engine is cold (around 700-1000 rpm). On park and neutral.

When it gets warm the idle would stays on 1500-1800 rpm on park and neutral. but when I put on the gear (D or R) it goes down to a 1000 rpm.

I rewett the solder joint on the idle control unit and clean the idle valve but no LUCK ! the idle still stays at 1500-1800 rpm when warm park and neutral. Replace the OVR or OVP, same thing no luck , idle still high.

Please help me. This car is my daily driver and I could not afford another car to get around since my other car 86 SAAB 9000 turbo Carlsson edition needs a fuel pump and sitting in my garage.

Insurance is expensive here in NY