Let us hope it is just a valve stuck open, but there is a problem with the Recon, in that the cam chain tensioner can break, throwing valve timing out, the piston can then hit a valve, bending it. Take the rocker cover off and check if there is a lot of clearance on one valve. However, to check if the timing has slipped, the clutch cover has to come off, a broken tensioner would then be visible, as are the timing marks.