1973 Continental Questions

Hello Bill,
I came across your contact info on an online forum about Lincolns and am hoping you might be able to help me with a problem I’m having.
I recently bought a 1973 Lincoln Continental Town Car with only 46K actual miles on it.
Car was running great until today when it suddenly started running TERRIBLE at idle and will stall out if I don’t give it gas. Actually it started idling kind of rough about two days ago and has gotten progressively worse.
At first I thought I might have gotten some bad gasoline or something. Unlikely though… The car runs smooth as silk and very strong at cruising speed.
When thinking about what this problem could be, I suddenly recalled that the headlights doors have not been closing properly when I turn off the headlights. When I go to use the car in the morning after parking it over night I have noticed that the headlight doors are only partially closed. The past two days the doors have been in the open position completely.
Since the headlight doors are vacuum operated ,(which I did not know until reading the owners manual today…), I suspect that a “vacuum leak” is causing the headlight doors to malfunction and may also be the culprit for the car idling poorly and ultimately stalling out if I don’t give it gas.
Do you have any thoughts or experience with this issue? Any advice you could give me will be greatly appreciated! Thanks!
Adam
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Hello Adam –
Those 73 Lincolns are real nice vehicles and are even better when they are running real well. If you believe that headlamp door vacuum leaks are your problem with the rough idle we will include a H/L door vacuum diagram in this reply for you. Vacuum leaks can occur anywhere that vacuum is routed. A set of Shop Manuals should be in your future though as these are a great help in diagnosing many issues. We have previously addressed Vacuum Headlamp door leak problems here on the blog and you may want to search some of earlier questions and replies using the search function.
Vacuum leaks can certainly upset an engine idle as you have stated but you must not overlook that the fact your carburetor may possibly be the culprit. Carburetors can accumulate fine debris from the fuel tank, floats can stick and valves can leak etc. This will upset the mixture needed for good combustion. I assume that the usual necessary “tune up” components such as ignition points and condenser, wiring and spark plugs are in good order. If you need any Shop Manuals, more advice or parts etc. be sure to contact us further.
Sincerely,
Bill