Im at a loss fellow cougar owners… Yesterday was a week since my 68 came back from a total engine rebuild and went to take it out last night and it started perfectly fine but a block from my house it felt awful all the sudden. A very rough idle and the whole car was shaking, it ran perfect on Saturday evening no issues whatsoever, hence why im at a loss.
loose a vacuum hose? distributor not tight?
^^^ +1 Those are the two things I would check first.
A clue for me is that it was fine and now it’s not. Something has changed in a few days time. Exact same experience after rebuild on mine and it was sediment from my rusty gas tank plugging up carb. Passed right through brand new fuel filter and plugged the carb idle circuits. If you have an old fuel system, it might be worth pulling the top off the carb to look for sediment in the bowl.
That’s a beautiful Cougar, btw!
Yeah, that too…
I would also check your plug wires and or spark plugs
Thank you all for the insight, it was to cold of plugs for the motor.
didn’t see that coming…
Good call from Superbond! So I guess the plugs must have built up carbon due to being too cold? I have been running Motorcraft SP459 platinum tips in mine, but wondering if the old original AF-32’s might be best for the original ignition systems.
Count me as doubtful. Maybe the plugs fouled really fast but I suspect that you may have an intermittent problem. Do you have pics of the old plugs?