SteveHobart 57 Posted August 31, 2018 Hi all! I have a 4.1 EFI in a XF SPack and it hunts at idle. Alternates between 500 and 1000 RPM constantly. Have you got any ideas on what to look for with this? Thanks Steve Sent from my iPhone using Tapatalk Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 31, 2018 Vacuum leak would be my prime suspectSent from my Pixel using Tapatalk Share this post Link to post Share on other sites
bear351c 10,270 Posted August 31, 2018 Yep, agreed. Make sure oil cap and dipstick are tight. Spray a small amount of Aerostart around inlet manifold, where it meets the head. Not too much.!! Revs will rise if it gets sucked in. 1 Jkmacxf reacted to this Share this post Link to post Share on other sites