I have a 70 Duster with NOS and MSD electronics will a bad stock amp gauge cause me to have problems with stock wiring..With the car off with the power on it works fine.But soon as the motor starts.The gauge moves all over the place its works when it wants to..Thanks need help ASAP..

Old ammeters have been a problem for more than one Mopar. Some folks have stories as bad as fire,smoke,etc. The firewall bulkhead is another trouble spot to check out too. All of the juice goes through the connector to the amp gague and back out. High resistance(old)connections cause heat and electrical failures.

Thanks for the quick reply and help I will check both..

We found this problem on a Duster my son had. Headlights worked just like a riding mower, light when running, pull up to a light, or idle, they'd dim almost out.

It was the amp gauge/wiring @ the gauge.

here are some more details on what the car is doing.The gauge left and halfway.. I'am running a MSD 7531 box and a nos control and The NOS work when it wants to like something is interfering also.Thanks for the replys and help..

i had a dash fire in my 68'dodge coronet with old amp gauge, i did the amp gauge bypass and went to a volt gauge, i did the Madelectric.com bypass, works great and even helped with the dim lights at idle

get under the dash and take a look. Mine was doing the same thing yesterday w/ some smoke! turned out the + wire was touching part of the frame. fixed it in about 1 minute. Those guages suck. You can bypass it by connecting the 2 wires together and that keeps all the juice form coming into the car.