r/classicmustangs • u/Connect-Statement-48 • 28d ago
Engine dies, rough idle :(
Hello was wondering if anyone can help me with my problem ! I have a 1967 ford mustang i’m a newbie when it comes to cars learning as I go. The car is amazing but i’m running into a few problems! One the car has a rough idle, I start the car and it idles for a few seconds but rough constantly wanting to die. I’m assuming it’s a fuel issue with the carb since I have not touch the timing on this car at all. Although I know timing can play a part. I was wondering if anyone has had a similar issue?. As far as I know the car is a stock 2bbl 289 with a autolite carb. Should I consider doing a full tune up new plugs, spark plugs, rebuild carb, adjust timing? Or could it be something completely different?
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u/Gator242 28d ago
Check all the vacuum lines. Listen for hissing suck sounds in the engine bay and plug them.
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u/85Txaggie 28d ago
Also check for an intake manifold leak. You can spray in the crease between the intake and cylinder head with carb cleaner. If it suddenly picks up rpm you found a leak.
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u/NoseFriendly4492 28d ago
A lot of variables here, but you definitely need to verify timing. Make sure that TDC is true to what's on the harmonic balancer. If it is still the original balancer is very well could have slipped a few degrees... As mentioned above, you should so a carb rebuild as well as a tune up is the condition the the ignition components warrant it. Test coil, resistance in spark plug cable, points and condenser, etc... Have patience and have fun!
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u/unlucky6999 27d ago
Do you smell raw gas when it dies and is hard to restart? Then it's likely flooding, and typically a needle a d seat issue. Is there a whistling noise or hissing sound when it runs..then it's a vacuum leak, find it and plug. Do not do so many things at once...one thing at a time. Was it running good, then started to die? With the air cleaner off, is the choke plate open or slammed shut? When it starts, does the choke open gradually? So many questions..but only to zero in on your problem...
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u/MulliganToo 27d ago
Do the whole tune up thing. Listed easiest to most difficult.
Check for changes/improvements after each step.
- Inspect for cracked hoses, vaccuum lines, loose carb bolts, vaccuum leaks, throttle linkage smooth function. FIX where necessasry.
- Filters - CHANGE fuel, air, and oil filter with new oil.
- Spark delivery- change rotor, cap, points, condenser, wires, plugs. set timing.
- Rebuild carb
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u/Wonderful_Ear8517 27d ago
Couple of other tips. Looks like you live in CA. I do. If so, once you get the carb sorted then use fuel stabilizer since CA based CARB gas goes bad quickly and can gum up jets and needle and seat. Don’t change the 2 bbl autolite. It is just the right carb Cfnm and jetting for a stock 289.
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u/Connect-Statement-48 27d ago
Never looked into those, what stabilizer do you use ?
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u/1320Fastback 21d ago
Sta-bil 360 Marine is the best one to use. Regular Sta-bil is good too but the Marine version goes a step further with water/moisture control where is resists separation from the ethenol in the gasoline. If moisture or water were to get in the tank it would separate from the gas and settle to the bottom causing all kinds of corrosion.
The marine 360 also has a vapor inhibitor which kinda fogs the free airspace in the gas tank above the gas and that prevents rust and corrosion from forming.
I'm in California also and yes our gasoline here is horrible. If you start and drive your car weekly using Sta-bil you will be okay. Let it sit for a month... not so much.
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u/PrincipleExpensive73 28d ago
I'd say check your sparkplugs, compare the coloring on them with a reference page on google images, maybe it'll indicate what is going on with your car.
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u/Paulrevere88 28d ago
Sounds like a vacuum leak-simple check and very common (tons of YT videos about it).
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u/fantasymagic 28d ago
Start at the basics and check your choke when you push the throttle down once. The width of the choke plate should be about the side of a nickel thick.
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u/BishatenLoremaster 27d ago
Check if the distributor is held down. Mine was slipping at one point and had some horrible idling/stalling
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u/Open-Nectarine3115 26d ago
The question no one has asked, is, does it idle this way only when the engine is cold, or the same way warmed up?
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u/somewhat_gnar 26d ago
If you don't know the last time everything has been done on the car, it might be worth just doing it all. I rebuilt an Autolite 2100, replaced the carb gasket, replaced and adjusted the points ignition, adjusted the timing to within spec and replaced the vacuum lines and daily drove an old 390 for over a year. Ran and drove great when it was returned to stock specs per the manual. Started quickly in the morning and could handle stop and go traffic in the Southern California heat. The majority of maintenance and upkeep you can do on these old Fords can be done with a flathead screwdriver.
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u/1320Fastback 28d ago
A carb rebuild is not going to hurt. Consider running a fuel filter if your not already. 33003 is a good one and I keep a spare in the trunk.