new 4 bbl, new intake, new kickdown and throttle cable, rebuilt dist, new coil(2), new ignition module(2), new fuel pump.......... car ran greaaaaat! for 4000 miles, absolutley wonderful, could not be any happier. THEN slight miss, then heavy stumble at idle, then it cuts out with hard starting. checked everything including valve lash, timing and plugs?????????? 1973 swinger 225 a/c but still not in.....................

please help

I feel your pain. Check for spark and check your fuel filter. I would put a fuel pressure gauge on the line to be sure your pump is up to snuff. Is the carb a Holley? I have had trouble with stability of float adjustment on these in the past.

Pull a plug wire and crank it while holding the wire close to the block. Don't hold it with you bare hands, or you will end up sitting on the ground saying "WOW!" or some equivalent.

Don't assume just because it is new, it is good.

Sam

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Heat can do strange things to ignition modules (and coils)

Get a heat gun and heat up the coil and ignition module and see if you can make it fail.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

changed fuel filter and carb is 390 holley,,,had ignition coil checked and am now on 2nd unit........found something interesting last night.......ignition wire tips where corroded and pulling off insulation. Wires are accel and only 5 months old. Car sit in garage overnight but drove car in heavy rainstorm a while ago. picked up replacement tips and will put them on tonight.

i meant to add.........checked coil wire first and got good spark......no spark from cap to spark plug.

Not sure I understand last phrase there. I remember my old Duster would not run right when it was damp unless I sprayed clear lacquer on the cap and plug wires on a dry day. Then it was good until I had to pull the cap for some reason.

Sam

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If plug wires are OK, bad fuel pump?

Olaf.

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Aspenized

so while I was putting new tips on.....noticed ash coming out of insulation ,from both sides of wire. I cut open a small section of wire and saw ash and charcoal where wire use to be. WOW! new wires( this time pre made) and presto-chango it cranked right over and idled like a champ. I had to pull out into the street and chirp the tires....HA!

In my earlier reply... I had fire from coil to cap, but no fire from cap to sparkplug.

Got it. This shows that new, (or almost) is no guarantee the part is good. You need better wires. The wires Dan turned me onto have been great. My old brain does retain the names of such things these day, but if you do not hear from Dan, do a search here on the forum. If it does not show up, ask again.

Sam

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Magnecor.com

Olaf.

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Aspenized

Good show. I have these on my car.
Sam

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Me too, they will outlast the engine and car.

Olaf.

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Aspenized

thanks.........Sam and Olaf!!!!!