What are your vacuum readings at idle?

[Tjn182]

I've been watching my gauge at idle the past few weeks trying to rub out my rough idle. It's the type of idle where you get a nice shake every second or so -- and it feels like you have a 400 cubic inch engine under the hood. During this my gauge read about 18-20 under idle and I idled around 750-800rpms.

I did some adjustments with my AFM -- having the flap door completely close at idle with the bypass screw almost all the way out. Since then my idle has smoothed out quite a bit... and the idle drops to about 620rpms (right around the little tick on the tach) and is much smoother. It slowly rises to about 700-720rpms yet my vacuum now reads 14-16.

What do you guys have as your readings under idle?

[Bill in MN]

around 20 at idle

[gol10dr1]

same here, approx -20 at idle, never looked at the RPM, but then again my car isn't exactly tuned so i might not be the best person to ask.

[90e34535i]

I have a Mass air flow sensor using a box to convert the voltage, and when id lower the air flow voltage at at idle, My mixture would still oscilate, but would hit like 15.5 to 1, and start to shake,

so i richened up the idle voltage so it didnt hit so lean when it oscilates the mixture, and now it doesnt shake much at all, a nice smooth idle, but it does idle pretty rich until warmed up(smells kinda bad), so i prolly gotta take a little off.

So maybe its your mixture going too lean at idle?

[Tjn182]

I guess I'll check for airleaks -- Or adjust the AFM some more. The car was driving kinda funny today... acted a little powerless unless I really got on it and made some boost.