Irregular Engine Missing?
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From: Sarasota, FL
Irregular Engine Missing?
Is there a good first guess as to what is causing erratic, irregular, now and then missing/coughing/hesitation? My 110,000 mile 
1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?
Thanks, Craig
1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?Thanks, Craig
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Is there a good first guess as to what is causing erratic, irregular, now and then missing/coughing/hesitation? My 110,000 mile 1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?
Thanks, Craig
1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?Thanks, Craig
Dan
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Always run clean fuel. Put a additive
in, if you think you have bad fuel.
Good luck
in, if you think you have bad fuel.
Good luck
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I think I'd start with the bulkhead electrical connectors which are known to work loose, corrode and cause sudden and related electrical system failure. Troubleshoot from there to ignition; switch, coil, points, wires, cap, rotor, ballast, any of which can be involved. In my experience intermittence is more likely electrical than fuel system on a stock vehicle.
Dan
Dan
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Is the miss more noticable on ecceleration? Something very simple to check is your ignition coil....
Last edited by dcamick; Apr 29, 2023 at 07:43 AM.
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If something was wrong and one was turned, it would be more of a constant miss, not once in a while as OP says. Personally I'd put your suggestion a little farther down the list, and see if the problem was located before we got that far down.
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Like other have said above, sounds ignition related or possibly bad fuel. For starters, check for moisture in the fuel tank and weak spark. Trace ignition power wire from Ign. Sw. to the coil and also ground side thru breaker plate. Not sure on Chevy but, most GM cars; the resistance wire for the coil power runs from the Ign. Sw. thru the firewall connector to the coil, whereas sometimes the resistance wire starts at the firewall or bulkhead connector. So if you just replaced wiring from after the firewall connector, it possible the wiring on the other side (interior side) could be suspect, namely the Ign. wire.
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Like other have said above, sounds ignition related or possibly bad fuel. For starters, check for moisture in the fuel tank and weak spark. Trace ignition power wire from Ign. Sw. to the coil and also ground side thru breaker plate. Not sure on Chevy but, most GM cars; the resistance wire for the coil power runs from the Ign. Sw. thru the firewall connector to the coil, whereas sometimes the resistance wire starts at the firewall or bulkhead connector. So if you just replaced wiring from after the firewall connector, it possible the wiring on the other side (interior side) could be suspect, namely the Ign. wire.
not on Corvettes. they used a ballast resister.
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Is there a good first guess as to what is causing erratic, irregular, now and then missing/coughing/hesitation? My 110,000 mile 1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?
Thanks, Craig
1964 0riginal L76 has been running like it was brand new for the past two years then suddenly I get sporadic hesitation? It really seems like water in gas and I hope that is all it is. However if it's mechanical, do I look at spark or fuel?Thanks, Craig
You could pop the fuel cap off & with a good flashlight see how the fuel looks? Never forget a long time ago changing out a electric fuel pump on a classic BMW after removing the pump under the back seat fuel tank access panel & looked down into the tank found remnants of water/rust very obvious by visual inspection..
Good luck, keep us informed.
Regards
Chalie
How old are the wires cap/rotor ignition items??
“ It’s the simple things that confound the wise”
let us know..
‘Chalie
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Thread Starter
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From: Sarasota, FL
How old are the wires cap/rotor ignition items??
“ It’s the simple things that confound the wise”
let us know..
‘Chalie
Plug wires 1000 miles old. Cap/rotor/points unknown. Will check these as I go down the list of suspects.
“ It’s the simple things that confound the wise”
let us know..
‘Chalie
Plug wires 1000 miles old. Cap/rotor/points unknown. Will check these as I go down the list of suspects.