I recently changed the battery on my 2002 ford focus and now it runs different. Well, it still feels smooth and sounds fine but the rpm will go all the way to 3,000 before it changes to second and third gear. It also makes a hard change of gears or however you say it. Whenever I change gears it feels hard on the car. What do you think it is? It used to change gears very smoothly before I changed the battery.|||The ECM has been erased and is going threw a relearning phase. give it a few more days.|||Automatic right? Its probably the difference of temperature. The warmer the engine the less efficient it is. It might just be reving higher because of that. Run it cold and see if the performance is still poor.|||When you changed the battery power was removed from the engine control computer. The computer controls the shifting of automatic and by having the power reset appears to have affected the transmission shift points. Call the local Ford dealer and ask them what to do about it.
As Roy above said it might go through a relearning phase.|||What you need to do is remove the battery cables again, leave it for about an hour or so, and hook them back up. what this will do is it will reset the cars computer to it%26#039;s default settings. Now, you will still feel it running rough for about 1000km or 600 miles because the car is resetting the codes in the computer. If it doesn%26#039;t change by 1500km, you should get it in to your mechanic to have a diagnostic done. there could be a wire you knocked off when you changed the battery too......... just check everything out and make sure everything is where it should be. you will be fine.|||Your computer has a memory in it that will be erased if the battery is disconnected, and it takes a while to re learn the stuff so be patient.
It has to learn all the sensors, and how you drive and other stuff, including the altitude where you live and it takes all this information and makes your car run better under those conditions.
