misfire

[64 200 ranchero]

when the car is at idle it is fine, when i give it gas and let off it misfires and after a minute it runs fine again, i thought it was my spark plug gap, i had it at 70thou which i know is high but the car always ran fine with it, so i tried gapping them to 50thou still misfireing. the only other thing i can think of would be my exhaust leak. any thoughts?

 

[MPGmustang]

bad plug wires?
bad spark plug?
bad ignition mod? (IDK DS)
bad advance can?
Timing moved? (pls verify) (maybe the clamp came loose?)

My memory when I "popped" when I let off the pedal was not enough gas, I have a 2nd dashpot that I wasn't using, so I tightened the screw and it went away.

just pushing ideas... good luck
Richard

 

[64 200 ranchero]

im thinking it might be the cap, its been a while since i changed it, the plug wires are about a year old but they are accel's so i dont know how long they last, plugs were black from running rich but i cleaned them. i bought the cap so i hope thats it, i plan on racing my buddys ricer soon

 

[64 200 ranchero]

argg i changed the plug wires, cap, rotor and i fixed the exhaust leak, it idles fine then if i gas it then let off quick it misses, then it go's away after 5 seconds, can it be my rockers are out of adjustment? when this happens my vac gauge fluctuates quickly

 

[MPGmustang]

whats your timing? are your timing springs good? un hook the vac to the dis, then watch the timing mark as you rev the motor, it should advance. if not your not getting spark at the right time causing the misfire.

I think this is due to improper timing and too much gas causeing the bad hard idle.

confirm that the mark is TDC, set timing to 8* with vac to distributor can pluged.

 

[rbohm]

8) i had a similar issue with my old 66 falcon. i worked with the idle mixture, and ignition timing.

 

[64 200 ranchero]

i backed off the accel pump adjustment, fixed it thanks