Could a weak battery or one that is going south be the cause of a rough idle or miss at a hot idle? Everything is smooth with the idle, revs nicely and idles great up until the temp reaches 180 deg and then it wants to idle down really rough to the point of a miss and surge situation.
Engine is a 451, solid cam 254/.520, MP electronic ign, MP distributor, chrome box, 800 Eddy carb, 20 deg initial timing. It will idle at 1000/1100 rpm when cold but as the temp comes up it will idle down to 600 or so. It runs really good except at idle. I'll have the battery tested here in the next day or so but just looking to see if this may be cause?
Low voltage to a Orange box will eventually kill it. It's struggling to draw amperage from a weak system. As it starts to go south the motor may start backfiring. Put a good battery in the car and change out the box.
Think it runs bad, try running an MSD with a bad battery.
