My amp guage is reads low at idle even when only supplyingpower just for fuelpump and motor. it gets worse as headlights or heat motor is used. it will go back up to charge when at about 1500 rpms. just concerned.
Have you checked for Voltage drops in your system? IE: what is the alternator stud reading vs what the battery is seeing at idle and 2,00RPM? It's not uncommon for the drops that are normally caused by poor connections to cause your condition. the other issue already mentioned is pulley sizing, but if you have multiple voltage drops upping the alternator output by whatever method is a band-aid. You should also have the alternator checked for output referencing the factory service manual
