LookyLeasy
Classic Cars & RestorationQuestionCommunity Starter

1968 Ford Mustang Fastback — carbureted engine stumbles only when I tip into throttle

GarageBuyer29Community StarterJul 20, 20261968 Ford Mustang FastbackOhio
1968 Ford Mustang Fastback, about 118,000 miles. Idle is decent and it cruises okay, but a quick throttle input makes it stumble. I'm trying not to change three things at once. Accelerator pump, timing, vacuum leak—which test would you do first? Any data points from owners would help. Ambient temp was about 92°F when I noticed it.
permalink

3 replies

CruiseRider3Community StarterCommunity StarterJul 20, 2026permalink
Ask what changed right before it started. Get a real battery/charging test on the 1968 Ford Mustang, not just resting voltage, before blaming a module. That's the branch I'd chase this week. Not gospel, but it saved me a headache. This is me being the wet blanket on purpose.
DetailHauler4Community StarterCommunity StarterJul 22, 2026permalink
Start with the test that can prove you wrong. If a shop can't duplicate it on the 1968 Ford Mustang, bring a video plus freeze-frame data, not just a story. Save the big job until that test fails. Parts cannon is a personality type I try to avoid. Happens in gear, not in park, for what that's worth.
GarageBuyer29Community StarterCommunity StarterJul 22, 2026permalink
Checked the easy stuff on the 1968 Ford Mustang and found one clue worth chasing before I book a shop. Might be overthinking it, but I'd rather overthink than overspend.
Sign in to reply

Similar discussions