Weak spark from coil to distributor cap. How do I fix it?

Is it a strong spark at the coil? If it is to weak it won't travel through the wire.

this can be caused by a weak battery check battery and charging system to verify a good working system. it could also be a weak coil not being able to supply enough output voltage for the ignition system. you don`t say if its weak coming out of the coil or at the plugs. if spark is weak at the plugs it could be a bad cap/rotor, ignition wires. it could also be an ignition module problem or pick-up coil in the distributor.

1995 silverado has a distributor, remove the the distributor cap, make sure the distributor spins with the engine. also make sure the ignition rotor is not burned out or have a hole were it makes contact with the cap. also make sure the cap has a good carbon inside to make contact with the rotor, at this time get a screw driver, put it on the end of the wire from the coil to the cap, don't touch the metal part of the screwdriver, it will shock you if good, so put it at 5/16 from any metal on the engine, bracket, alternator , thermostat housing no matter, some one turns the engine over, check to see if the coil produces a spark, if the rotor turns, if ok it should have spark on all the wires, if it has no spark, remove the wire from the ignition coil and check if you have spak at the coil, if you have no spark, try getting a wire lead, connect it from the battery ground on one end, a screw driver on the coil to check for spark, and the other end of the wire with the key on, touch the - negative plug on the coil, that should produce a spark, if not spark yet, make sure you do have power at the coil with key on, if you do and it doesn't produce spark, replace coil. if it does spark but it is weak or yellow in color, replace coil. if coil is fine, replace distributor module,

I suggest replacing the distributor cap and the lead.

I guess you could have the ignition analyzed on an oscilloscope. Maybe a tech could see something then.
I always heard the only gap was the spark plug gap-the rotor has no gap-are you sure you got the correct rotor? And does it touch the top distributor cap coil wire tower?

Let us know. It is a mystery worthy of a solution.

try cleaning the distributor cap and rotor arm and replace spark plugs and leads. hopefully this will fix the weak spark

1) The primary circuit: is battery, cap, resistor, capacitor,switch ignition+secondary circuit spark plug, distributor, high tension wires+spark plug.
the mayor problem arise in the coil and distributor, And the most common problem INCORRECT Choice de spark plugs or improperly gapped.
Rememeber the coil send 20,000-30,000 Vdc for spark plug.
Test with a screwdriver , pull out the center wire from the distributor cap and hold 3/8inch from a good ground. Crack the engine, if there no spark, or the spark is weak, the coil is defective or the high tension wires.
2) Bypass by a moment the baas resistor with a jumper wire while cranking engine If the engine starts, replace the ballast resistor.

God bless you.

You replaced the cap and rotor? If you still have spark to cap but not out I would say weak ignition coil.

cps located on the top left side of the bellhouseing

do you have spark from The coil if not check all grounds. 5 volt referance ciruits and tach signal from pick up in distributor to coil