I'm having the same issue along with bad rod bearings , I thought it may be related. It hadn't done it all winter , but recently it has stared again , normally its at 7-8,000, but sometimes its revs to 11-1,800 before I kill it. Then ill pull over start it, usually it'll rev at 2,000 ,then I start 2-3 more times before it idles back to normal, sometime as low as 500. But it gets me to work everyday and offeoading when I have the gas. 293,173 Miles and pushing.