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1965 Mustang surges, chokes, and dies at highway speeds.

2509 Views 5 Replies 5 Participants Last post by  Nashville'65
Hello everyone!
I have been watching the forums on this site for a while now, and have gotten some very valuable advice from here so I decided to go ahead and make a profile. So- I have a 1964 1/2 Mustang 289 with a Holley 4 barrel carburetor, MSD ignition, and a (very recently) rebuilt c4 transmission. I originally took it to the shop because one day park just decided to disappear, and i could feel it slipping between second and third gear (or so I thought). Apparently it really was slipping between those gears, but that's not what i was feeling. As I was driving home from the transmission shop, i was doing about 70ish on the freeway when i started to feel a vibration through the gas pedal, and eventually the car started surging and bucking and eventually stalled and died. It was doing this before, and of course is still doing it now. I'm about at my wits end here. Does anyone have any ideas what could be causing this? It starts and runs fine, and drives fine at city speeds, but any time I'm doing highway speeds for more than a few seconds, it's the same old story...

Please help!
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Welcome to AFM! I moved this to the Classic Tech section to see if the gurus here can get you squared away. We'll get you figured out.
Thanks for joining!
sounds like a carb issue to me

how old is the holley 4bbl?
Check fuel delivery pressure, potential for vapor lock, clogged fuel filter, clogged jets on carb secondary circuit.
I had the exact same problem last week. It ran great on the side streets but on interstate it would choke and die at highway speeds or even just accelerating on the ramp. Putting in a new fuel filter seems to have fixed it (I have a freshly rebuilt autolite 2100 2bbl carb). I think mine wasn't getting enough fuel. Let us know what you find out.

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I agree with NAMLOH, def. check your fuel filter...and probably just replace it. At idle and slow speeds/low RPM's, the engine "asks" for less fuel...once you get it running on the highway it's possible not enough is getting through.

Let us know if that doesn't work-- we'll think of something else!
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