Hi Guys, Happy thanksgiving to you all!! I was browsing through the net for my issue and found this group. So I thought I'll ask the group's advice before I go to the St(d)ealer!! I live in Chicago suburbs. I have a 2003 civic LX auto with 68000Miles. During these cold days (20 to 35 F), the car is sluggish in pick up when the engine is cold. It is as if I have a 500 Lb load on the car. The gears shift at higher rpms, but there are not issues with gear shift. Once the car is warmed up, the pickup is fine and acceleration is normal. But I notice the vibration level is little more. Milage dropped a little (from 32.5 to 31.5) after the service and I assume that is due the the lower temperatures. Now I'm about to fill the tank again and I'll probably get ~28mpg. (300miles for 11 gal of regular BP gas). History of the car: I Bought the car in Aug-08. The previous user is an ASME certified mechanic The car has a provision for a hitch to mount (This is to let you guys know that the car may be used for towing) Previous oil is 10W30 Valvoline durablend Driven about 1000 mi/ month so far I'm a very smooth driver; no rapid accelerations, no violent braking; no racing in the stop lights with other cars. Always driven by me only. No passengers in the car. I drive 28 miles per day in mostly city roads; no freeway drive. After 66000 Miles, "maintenance required" lamp is on and is still on. But the check engine light is off. About 1000 miles ago I changed oil at Walmart ( I supplied the 5W30 valvoline durablend oil and they did the change. however I did not supply the oil filter with the oil. I assumed that they replaced the filter and charged me. I do not have the service receipt with me now). However, Honda manual recommends 5W20 oil. I suspect that the oil filter has not been replaced and the oil bypasses the filter and eating the bearings and cylinders resulting in higher blow-by and loss of compression resulting in power loss. Can this be true? Is there any indication to the driver that oil constantly bypass the filter like check engine lamp? Or is it something to do with the tranny oil (I donno what oil is in there!) or the throttle position sensor malfunction or is it the O2 sensor? Am I supposed to get a "check engine" if O2 sensor is faulty? Is the "maintenance required " supposed to be gone after the oil change? Do you suggest oil change again with 5W20? Please let me know your thoughts. Thanks in Advance, Victor