Thread: pulsating noise at idle or while driving.

I'm hoping to get some insight here, never had this happen before. But when the car is running I can hear a pulsating noise, not overly loud but its on n off every 3 seconds. There is no change in rpm at all. No new repairs done recently. But last night my tank was on empty and I a strong odor of gas in the car that lasted about a minute then went away. That was the first time this has happened. Any thoughts or suggestions? Thanks guys.

Could be the EBCM pulsing the ABS pump as a self check. Does it constantly do it or only for a few times?

It constantly does it. But there no surge on the engine no drop or rise in rpm and it does it when I'm stopped or driving. I don't believe its my abs.

Since it does it while running in park then pop the hood and take a listen. Since it does it every 3 seconds it would probably be easy to pinpoint.

I tracked the noise. It doesn't do it all the time but its behind the blower heater controls. Gonna hv to take it apart and investigate. Any info before I do would be appreciated.

Thanks for ur reply. If I understand correctly, behind that control there's vacum lines?? My question is if I take the contril part off while its running, can I risk screwin sumthing up?? I've always done my own work and pretty good at it. But I never did pull out the tstat controls before.