Hey everyone.

Yesterday while driving in parkway around 40 mph, my vacum gauge showed almost 30 In.Hg. when decelerating.
When Idling usualy shows 18-19 In.Hg. of vacum and while driving/decelerating goes to 21- 22 the most, it was litle frightening.

I got a autometer boost/vac gauge, 22K Miles old motor.
Does anyone know what the hell was that???

Thanks, John.

 

Sounds normal to me...Idle on a stock healty FD with good compression is anywhere between 16-19inhg.

It always pulls a vac when you decelerate I have never really looked how much vac it pulls when I let off the gas but it's up there in the 20s

So to me and my own observations I don't think you have anything to worry about. Now if you were seeing 30PSI that would be different.

 

I usually hit 22-25"mg but 30 is kinda high but i really cant think of a reason why that would be bad.

 

It's perfectly normal. The engine pulls vac at idle and pulls more when you decel because the engine is spinning at higher RPM while the throttle butterflies are closed. Pulling the same amount of suction through a smaller orifice gives more vac.

 

I know its normal to se 20-21 In.Hg of vac. when decel. but 30 is litle to much dont you think?
I was thinking the gauge maybe crapping out to.

 

**** If I seen 30 lbs of boost, I'd probobly see my rotors flying out all over the parkway, lol.

 

I really doubt there is anything wrong. I think people are WAY too paranoid about some things.

If you notice the gauge showing some weird things on acceleration or idle, then I would worry. Other than that, just drive the car and have fun.

 

Thanks guys, I do get paranoid sometimes as everyone that knows and loves they're Rex as I do.

Thanks again for taking you time and answering my question, that made me feel much better.

 

Actually it's quite the opposite. The more vac the better; at any RPM. What this illustrates is the integrity of the sealing of the combustion chamber and intake system.

Go worry about something else

 

Thanks. hehhehe.

 

And believe me, there's lots to worry about

 

Someone should sticky that phrase. LOL

 

Yes...

 

You guys are such crack-up's....

 

my thoughts exactly!