okay heres the thing i bought a car from a fellow h-t member and ive been having problems with the idle. not to mention the taach doesnt work. i need to resolve this. My tach does not work on my LS tach. Everything else works though. ive checked the tach wire and it has voltage from it so i dunno what could be wrong. The idle is very rough when i start the car and maybe a little after. id have to take long trips before it gets a little better. still rough at times though. and at times it would want to die. I'd have to take like an hour trip for it to get a lil better. but even that....i dont like it and want to fix it. can anyone help or had similar problems?

 

Clean out your iac valve or try using a known good one.