Okay, my eclipse has been acting weird. When I press on the gas the car accelerates in a weird way. It takes off sometimes and other times it feels like it's lagging. I recently changed the air filter from the stock one to a high flow K&N filter, supposed to add about 2 hp. I heard somewhere that you are supposed to reset the ECU anytime you change the stock configuration. I thought the two items might be connected, but I'm not sure.

yes, whenever yo change something, you are supposed to reset the car so it knows it's there. simply unplug the + side of the battery and let it sit for about thirty minutes and then plug it back up.

Thats what I thought. Thanx!

I never heard of such a thing.

When you "reset" the ECU, you essentially rivert the ECU back to "reading
the factory set parameters (like a factory default).

When you drive the car, the ECU is comparing data received ( from the Crankshaft sensor, camshaft sensor, TPS, water temp, etc...) to factory programmed maps. If one of these parameter on the factory program is exceeded significantly, the ECU throw a check engine light and stores the fault code.

When more volume air is "sensed" (adding an intake system) the ECU refers to the factory program map for that amount of air flow and compensate with fuel, ignition timing, etc.. :)

Similarly, if you would add a turbo kit to a stock OBD ECU, it will not "run" right!!!! :devil: Why? For one, the stock ECU is not programmed to "deal" with that volume air flow and would the performance and :devil: reliability of the engine will be compromised.

But with temperatures changing and altitudes varying the computer automatically compensates for these changes as with an intake or k&n filter so therefore disconnecting the battery is a waste of time. By disconnecting it the computer will have to relearn everything and if the mod is so drastic to change the computer's parameters it would turn on the check engine light such as removing the catalytic convertor.

there was no need to reset the ecu from a little air filter.

mittech, usually when adding a CAI to the 3G, it usually causes idling problems b/c the little bit of extra air that is coming in. so you reset the ecu so that the idling issues will go away.

and its actually disconnecting the negative battery terminal, not the positive.