Over the past year and a half I've dealt with terriable gas milage (10 miles to the gallon actually) and am at my whits end. So far I've replaced plugs, cap, rotor, wires, vaccum hoses, and carb (replaced a little over two years ago with rebuild unit). Engine is a stock 305 H.O.
I'm going to be changing my coil in the morning in hopes that maybe it's related to that but I'm not sure that that will help. Is their anything I'm missing here? Maybe something else i should look into? Two and a half years ago i was getting 18 mpg so I know that this car is capable of better.

 

Other possible causes are:

• Dragging brakes;
• Restricted exhaust;
• Improperly adjusted or leaky carburetor;
• Weak/failed oxygen sensor;
• Weak ignition;
• Worn camshaft lobes;
• Incorrect valve or ignition timing;
• No timing advance;
• Poor alignment;
• Insufficient tire pressure;
• EGR leakage;
• PCV or other vacuum leakage;
• Improper lubrication;
• Driveshaft angle too high;
• Valves sticking or insufficient valve lash;
• Inadequate coolant temperature;
• Failing accessories creating excessive load;
• Poor driving habits.

I'd start with checking the carb adjustments, and making sure the carb isn't leaking from the underside.

 

Did your coil test as bad or are you just replacing parts? If you a just throwing parts at it in hope of fixing, it's an ineffective and expensive way of repair. If you don't already have a manuel for your car get one. Chiltons is better than Haynes.

 

the insulation on the red wire coming out of the coil melted at the base so the coil definatly needed to be replaced. i would assume that that would replace atleast part of the problem.