1965 Ford Mustang rough acceleration

REDPNY

MEMBER
1965 FORD MUSTANG
V8
2WD
AUTOMATIC
120,000 MILES

Here we go! Changed LHS exhaust manifold (cracked) and spark plugs. Went for hour drive drove fine. Fuelled up (premium), 5-10 minutes down road started stuttering and hiccuping. Got home and dropped fuel and put fresh fuel in thinking it may be bad fuel. Startes fine and idles fine, in park it revs crisp and clean, once in gear it farts and splutters and hesitates. It has poor power. Checked trans fluid fine.

Issues which may or maynot be related:
recently installed rebuilt 4100 autolite carb 4 barrel. Can't get secondaries to open. Also sometimes there is exhaust fumes coming out of air cleaner.

your help would be greatly appreciated

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Hi redpny, Welcome to 2carpros and TY for the donation.

If you so sure the tranny is not slipping -do below

Check the carb side:

Choke plate fully opens within 3 mins of start up and not closing at idle and part throttle- check float level and power valve, accelerator pump funtioning correctly-should be squirting fuel when throttle is pull back, misrouted vacuum hose or leaking and check fuel pressure.

Check and test the thermostatic aircleaner and heat riser are operating correctly-

Ignition side:

Points -gap/dwell is correct
Vacuum advance and ignition timing