When I start my 2002 Ranger the voltage meter reads lower than normal but not out of the normal range as indicated on the gage. Once I give it a minute or two the needle goes to the normal position. If I shut off the engine and restart it does the same thing - reads low for a minute but eventually goes to the position where the needle always resides. I measured the voltage with my volt meter and when first started the voltage is about 13 volts while the needle reads low but when the needle is in the normal position the voltage is around 14 volts. The battery cable look OK. When driving the needle can read lower than normal but also moves to normal - reading hi and low..

Any ideas?