My 1976 Lincoln Mark IV is having some issues that I’m guessing have to do with fuel delivery. For the past couple of days, it would have a really rough start (sometimes including a couple of backfires) and stall a couple of times, and then it would run fine for as long as I needed to. It only did this once a day, but not necessarily the first/morning start. After work today, I had a rough start, and then it kept stalling as I drove it. It stalled 6 or 7 times before I was able to get it into a parking spot and get a ride home.
I tried replacing the fuel filter when I first started to have problems for a couple of days ago, and this seems to have helped for a little while, but since then I’ve started having issues. I also tried replacing it again today when I was having the stalling issues, but it didn’t help.
I’ve replaced the fuel sending unit, all of the rubber lines, and replaced the mechanical fuel pump with an electric one back in the winter when I was having a complete no-start issue. To me, it seems like it would have to be related to the carburettor, since I’ve essentially replaced all of the rest of the fuel system components, but I’d love any other ideas anyone may have.
My Ford truck has a 302 of similar vintage. It will sometimes act up like that all of a sudden. For months it runs perfect, then one day I start it up, and it idles poorly, stalls when shift into D, etc. Usually the casue is a vacuum device that is leaking, or a split vacuum hose. That allows unmetered air past the carburetor and cause it to run too lean. The effect is worst at low speed and idle, not noticeable at highway speeds. So double check the problem isn’t that before presuming it is a fuel or carb problem. one common source of device leaks for me is the gadget that opens the hot air path to the carb in the air cleaner, it has a rubber diaphragm that splits inside.