Having problems with your Toyota Corolla ?
Car revs drop when using electrical items - Corolla Toyota Cars & Trucks
To some degree this is normal, if it seems worse than before (I assume you have owned the car for awhile) then it is possible the battery is starting to go bad, if the battery is in a low state of charge then the Alternator has to work hark to keep the system voltage up, this takes engine power, up to 3 HP depending on the AMP rating of the ALternator, on bigger engines this will not even be noticed, on small engines like yours it will be noticed, one question, have you added anything that might be pulling allot of power? like a sound system amplifier? if so that is dragging the engine RPM down and you may need to upgrade the alternator to a higher amp rating unit.
Repair Help & Product Troubleshooting for Toyota Corolla
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