Took my 72 Corvette 454 out for a run,
My issue is without any warning I suddenly lose power for a split second, it's as if you are driving and you would turn the ignition off for a split second and then turn it back on.
It does this 3 to 5 times while driving for about an hour in the city, even on the highway cruising at 60 MPH it cuts out for a split second.
Where do I begin to find the root cause of this?
Coil? Points? Distributor cap? Ignition wires?
Spark plugs? Gas? Gas Filters? Fuel pump?
Carburetor?
How do I find out what is causing the loss of power for a split second?

I got this response from a corvette owner:
If it dies for nearly a second, then the ignition is essentially 'dead' [all cylinders]. That rules out plugs, wires, and distributor (mechanical part). It also rules out the rotor and cap _except for the central feed paths_; but such an intermittent fault in those items is highly unlikely. That leaves coil, points, condenser, electrical wiring in distributor and coil power supply voltage from the vehicle. I just traced down a weird problem with mine that was not too much different. It turned out that the l
ead wire from the distributor to the coil had an intermittent short. The brass ferrule (strain relief) clamped onto that wire [inside of the dizzy] had worn through the insulation...and when vibration/accel/decel forces caused that brass piece to contact any metal, the ignition shorted out. Wierd!!

My bet is that it is an electrical fault: either in the voltage feed to the coil, the trigger line from the dizzy, or the coil itself (swap the coil out to test). You could hook a digital voltmeter up to the coil power feed line and to chassis ground with some long leads so that it could be inside the car. Take it for a spin and see what happens.

I changed the coil still same issue.
Help please

:doh: Took my 72 Corvette 454 out for a run,
My issue is without any warning I suddenly lose power for a split second, it's as if you are driving and you would turn the ignition off for a split second and then turn it back on.
It does this 3 to 5 times while driving for about an hour in the city, even on the highway cruising at 60 MPH it cuts out for a split second.
Where do I begin to find the root cause of this?
Coil? Points? Distributor cap? Ignition wires?
Spark plugs? Gas? Gas Filters? Fuel pump?
Carburetor?
How do I find out what is causing the loss of power for a split second?

I got this response from a corvette owner:
If it dies for nearly a second, then the ignition is essentially 'dead' [all cylinders]. That rules out plugs, wires, and distributor (mechanical part). It also rules out the rotor and cap _except for the central feed paths_; but such an intermittent fault in those items is highly unlikely. That leaves coil, points, condenser, electrical wiring in distributor and coil power supply voltage from the vehicle. I just traced down a weird problem with mine that was not too much different. It turned out that the l
ead wire from the distributor to the coil had an intermittent short. The brass ferrule (strain relief) clamped onto that wire [inside of the dizzy] had worn through the insulation...and when vibration/accel/decel forces caused that brass piece to contact any metal, the ignition shorted out. Wierd!!

My bet is that it is an electrical fault: either in the voltage feed to the coil, the trigger line from the dizzy, or the coil itself (swap the coil out to test). You could hook a digital voltmeter up to the coil power feed line and to chassis ground with some long leads so that it could be inside the car. Take it for a spin and see what happens.

I changed the coil still same issue.
Help please

I cannot see any loose or broken wires, checked the fuel filter in the carb, super clean.
Still have the immediate loss of power for a second on off on off.
Help please

I agree. It sounds like an electrical problem to me. As such, it could be anything from the ignition switch to the distributor. If your ignition switch is the original, it now has MANY miles on it and it wouldn't hurt to replace it based on usage alone.

The insides of ignition switches are coated with a grease, and after a long time, that grease hardens so hard, the contacts inside fail to make contact. You can open the switch up and clean out that hardened grease, but it's a lot easier to change it.

You could also try tugging on all your 2 distributor wires when the engine is running; to see if you can make the engine die. Whatever is the case, you sure don't want your engine to die when you're far from home.

I agree. It sounds like an electrical problem to me. As such, it could be anything from the ignition switch to the distributor. If your ignition switch is the original, it now has MANY miles on it and it wouldn't hurt to replace it based on usage alone.

The insides of ignition switches are coated with a grease, and after a long time, that grease hardens so hard, the contacts inside fail to make contact. You can open the switch up and clean out that hardened grease, but it's a lot easier to change it.

You could also try tugging on all your 2 distributor wires when the engine is running; to see if you can make the engine die. Whatever is the case, you sure don't want your engine to die when you're far from home.


I checked all the wires, changed even the coil wire to the distributor.
Very strange Corvette was running fine then it started to cut out, at times it felt like I was riding a bronco horse.I let it idle and you can hear the intermittent engine idle.
WHAT is going on with my Corvette???

Check the condition of the breaker plate's braided ground wire. The braided ground wire that is attached to the breaker plate and goes to the body of the distributor; preventing current from passing through the bearings in the distributor.

Are you still running points in the distributor? If you are running points, are they in good condition? Or you're ignition coil may be momentarily arcing from the center tower down the side.

Are you sure you're losing power for a split second? Or could it be something else that FEELS like you're losing power? Like the pinion bearings momentarily seizing up from lack of lubrication? Have you checked your rear end lube lately? Or maybe your emergency brake shoes adjusted too tight and momentarily grabbing? I'm trying to keep an open mind on this and considering all possibilities. And I'm also running out of ideas.

If you find out what's causing this, please let us know what you found.

I had a similair problem many years ago. The fault was a pigtail on the capacitor inside the distributor. At a certain advance angle the lead would contact a ground and kill the engine. As the engine slowed down the advance changed and removed the ground.