b16a1 first gen on a 90 hb si

why do i have an high idle its at 2K..what could be the problem..could it be my intake manifold? im using an intake manifold off an 99 si b16a2 and its on a first gen b16a1..?vacuum issue? need help..also will the cable clutch off my 90 hb si work fine or will i have to use the one off an 90-93 teg..cause at first everytime i shift into gear it would be hard then on reverse ti would grind like crazy...then i tighten clutch cable really tight then it would work for a bit!!any info on that ..please help