ok i have had my 95 supercoupe for about a week now and since i have had it the tach has not worrked properly it started out that it would work fine for a while then stop working, but now it never works. it idles around 700 rpms and when you give the car gas the tach will hessitate then jump up to about where it should be then if you give it too much gas it just fall down to 0 rpms. and when the tach is doing this the car runs poorly , it has a slight miss and a rough feeling idle. i do not know what is wrong i have read a few threads and thought what it needed was a new cam sensor or crank sensor, so i went ahead and replaced both of them becasue they are cheep enough and it still isnt working. i do not know what to try now i am all out of ideas can anyone help me