I bought a porsche 944 1986 and whenever I drove on the freeway and slow down before the exit the idle keeps going up and down. It's like the revolution goes up and down until I shift it in any gear.
Sounds like a bad air idle control valve. https://www.youtube.com/watch?v=30Ctw8BoNog
Search Porsche 944 Questions
Porsche 944 Experts
Related Models For Sale