How many inches of vacuum should my 3.0 be indicating?

[edgarcia737]

Hi everyone. I just replaced my air box and engine idles fine but lacks power and backfires until I get to around 3500 rpm. So I connected a vacuum gauge to the brake booster connection and it's only indicating about 10 in. hg.. That seem too low to me. But it idles fine.

I'm going to check fuel pressures today at the WUR and fuel pump. Also I'm going to borrow another vacuum gauge to cross check. Since my gauge is about 35 years old

thanks

[rattlsnak]

10 in at idle? should be at least 18...

[47silver]

great info is there a chart on the vacuum per 1000 rpm?

[edgarcia737]

Where's the vacuum chart? I think I have a leak. I'm going to isolate the decel valve and see it there's a difference. Thanks guys