I am wondering what kind of vacuum you guys get with a relatively stock engine. I am getting about 18 in Hg +/- .5 in Hg. The reason I ask is at times the engine will idle rough (generally once it is warmed up). Things I have replaced are the hose running from the evap solenoid to the TB, the o-rings, the intake gaskets and the throttle body gasket. The interior vents are working fine so I don't think there is an under dash leak. Thanks in advance.

 

18-20 is about normal for hot idle.

 

Got tune up lately???

 

I did the plugs last year and replaced the wires roughly a month ago. I'm suspicious of the ignition though. Once or twice a week I will get a backfire from the tail pipe.