crazyjam

see this website for Gary's cure: http://www.geocities.com/hobiegary/hesitation.htm

Last time I filled the oil filter as much as I could. I think the air pocket still existed though. It is very strange how it correlates with oil changes, to a T.

My 1998 Subaru Legacy has hesitation on acceleration between 1500 and 2500 rpms. This starts to occur after oil changes, and usually lasts for 3-4 weeks. Searches of websites have indicated that an air pocket in a new oil filter creates an initial vibration in the engine when it is first started up after an oil change. The knock sensor incorrectly reads this as an engine knock, transfers the info to the ECM, and subsequently retards the ignition timing to -10. This has happened three times in the past year, always after an oil change. The first time it went away on its own after 3-4 weeks, the second time I followed a procedure for resetting the ECM and the knock went away. The procedure for resetting the ECM is to disconnect the negative battery cable for 3 hours, then let the car idle for 15 mins without touching the gas, then turn the car off, and restarting and driving around for a while under normal commuting conditions. This time that procedure didn't seem to work. Anyone have this problem???