66 mustang 289 stalling

Asked by May 08, 2017 at 12:59 AM about the 1966 Ford Mustang Base

Question type: Maintenance & Repair

I have a 66 mustang with the 289 (not the high output). It's only got about 40k miles on it. And
when I bought it 2 years ago, it ran fine. Last year it ran fine until about halfway through the
summer, then just started stalling out at any rpm close to idle. Didn't matter if it was warm or cold.
I have a brother very knowledgeable on cars who did points, condenser, air cleaner, took apart the
carbs and completely cleaned it. I think he also did plugs, wires and distributor. It ran fine for a
couple weeks then started stalling again. Any other ideas?

3 Answers


Check the timing.


The stuff they call fuel today is really hard on older vehicles carburation, fuel pumps and fuel lines, I had a few older car in my shop when this junk started getting pumped, I had to overhaul the carbs with the new fuel resistant componets, replace all the hoses with the multi fuel design and replace the fuel pumps with the new design diaphragms, then reset it all just to run the fuel. I do hope you have already done the valves to handle the no lead fuel by now, if not then add some lead substitute to the fuel to prevent burning a valve. Some old hot rod dears have used StaBil Marine in the fuel to help combat the degrading effects on older vehicles but eventually they have to update.


The issue is either ignition or fuel. These old cars are much simpler to narrow it down. I would guess it's a fuel issue. Might be a carb issue. Your brother took the carb apart? 2 bbl or 4 bbl? I wonder if something didn't go back together correctly or came lose. When you start it does it idle ok? Can you give it more gas and increase the RPM or does it stall when you give it gas? tennisshoe is right, you need to replace any old soft parts in the fuel system as this current fuel will eat up those parts. I need more info as to what it is going to trouble shoot it. Look inside the carb and see if it is squirting fuel when you give it gas. Could be a gas line issue depending on the shape of your gas tank. So if gas is coming into the carb then it is an ignition problem. You replaced the right parts but they have to be replaced correctly. Anyone of those put on incorrectly will cause running problems. So it runs for a short time then dies? While you are driving it or in the driveway?

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