I am running a vacuum/ boost gauge in readiness for reinstalling the supercharger back soon.

I am getting erratic vacuum each time I drive. Sometimes it reads -10 hg vacuum and whenever, i stop the car and eventually restart the vacuum readings can got to zero at idle or other times it could be somewhere in between.

It changes each time I drive.

I have checked for vacuum leaks and sprayed maf cleaner around injectors and joints. I just dont understand why it can be pulling normal vacuum and after restarting its totally different.

I know that most people don't run vacuum gauges in a stock car so I am not sure if its normal.

Any ideas?

 

erratic ender on the Guage is the most likely....

 

Thanks, I will check the connections and if necessary purchase new sender if possible.