Dead cylinder help

[67ChevyRedneck]

So my truck has essentially been parked for months. I had done all I could do to it at the time, and it was still running poorly, so I moved on to get my mustang ready for summer. It has been running great since 2002.

It has a 350 with HEI. I bought a fancy timing light with the clip on end. I got the bright idea to check all the wires tonight. All 8 had good solid spark at the top near the cap. I checked near the plugs as well... all good except #3, it had a very intermittent & poor to no spark. Sweet, I thought, bad wire. So I run the crimp up the wire, starts working about halfway up. Just to double check, I moved a "good" wire over to #3. Same thing, good at the dizzy, then halfway down goes to crap.

That seems very odd to me... would a bad plug cause that??? I didn't have time to pull it, it was already getting dark out when I had the bright idea of checking...

Any input for stuff to play with tomorrow? Trying to trace this demon down I've cleaned all the - connections, rebuilt the carb twice, fuel tank is new and fuel filter is clean, replaced fuel pump anyway, completely new dizzy complete with all new guts - coil, module, cap, rotor, etc... What sucks I that I'm pretty sure that while they are about 3 or 4 years old, the plugs & wires only have about 5 or 6K on them.

[Wrenchbender Ret]

It is probably a shorted spark plug. The gas we get now will carbon up spark plugs real easy if running a little rich or idleing & low speed testing. It could be getting oil on it or the porsiline is cracked.

[67ChevyRedneck]

My dad finally sent me a text back, he agrees.

I hope this is it, I really miss driving the old girl! I started an awesome new job last week that's only about a 15 mile round trip from the house and I hope to actually DD the truck again.

[In The Ten Ring]

Another fellow on here or someplace suggested pouring in Marvel's Mystery Oil into about every 3rd gas tank full due to the crap they sell for "gasoline" these days.

[67ChevyRedneck]

It's possible it was the gas.

The truck sat for about 8 months with a bad rear trans seal (yoke was scored). I finally bought a yoke and ran the truck for a few months when it started running bad.

With everything else being new, hopefully new plugs/wires will take care of it.

[BB72CHEVKT]

I would get the remainder of the bad gas out of the tank.

[67ChevyRedneck]

She's ALIVE! Bad plug. There's not a lot of fuel left, about 1/8 tank, I'm going to burn the rest of it before I add more to it, then change all the plugs and rebuild the carb with an actual edelbrock kit I bought.

But yeah...