Classic/Antique Car Repair: 66 mustang rubber-banding, rotten egg smell, spark plug wires


Question
Hello,
I have a 66 Mustang with the 6 cylinder engine.  My car jerks like a rubber band when I start to accelerate in first gear, and when I am driving at a constant speed.  It has a new distributor with a Pertronix electronic ignition replacing the points & condensor.  I think the timing and carbeurator are adjusted correctly, but I could be wrong - particularly regarding the carb.  Maybe too rich or lean?  Any ideas?  
Thank you.

Answer
Hi Terry:
If you are running rich or lean, you should be able to tell. Rich= "small gas / rotten egg smell, black exhaust smoke, popping or backfiring. If  you are running rich, then your plugs could be fouled at this point.

1. Check the spark plug wires to make sure they are on tight and are not arcing. If you hear ticking sounds while idling, you may be arcing. Also you can check this in the dark to see if you see any sparks escaping from the plugs. This means you have loose connections, and most likely fouled plugs by now.

2. Check and replace the fuel filter (if it hasn't been done lately). This is many times overlooked. A dirty fuel filter could be blocking gas flow, causing this jerking problem. The jerking motion means the fuel supply is being cut off abruptly, so the filter replacement should fix this. If this is the problem, your plugs should be fine.