I didn’t see it mentioned anywhere in this topic, but your car uses an oxygen sensor to optimize the fuel mixture. Unfortunately, you can’t use a OBD scan tool to check it.
The car should still run even with an inoperative ECM and odds are the mileage tanked because any air bleed functions in the carburetor have stopped and the ECM controlled ignition timing was not advancing as it should with the timing remaining in a retarded position. That would kill the mileage and also account for the lack of power.
My memory is very hazy on this but I think that the Canadian versions of these cars back in the day used a vacuum advance on the distributor instead of electronic controls.
I’m assuming you’ve done the obvious things like checking for gasoline leaking onto the ground, etc.
A good shop would check the engine exhaust with their exhaust analyzer and tell you if there was unburned gasoline in the exhaust.
The cheapskate version is to use your nose as the analyzer, just smell the the exhaust fumes for any gasoline smells. Use common sense, only take a brief whiff and move well away, as exhaust gas is not healthy to breath.
I’m guessing there’s some unburned gasoline being piped through the engine. Suggest then ask your mechanic to test the carburetor, especiallythat the choke is properly de-choking within 5 minutes of starting . If the choke is ok, check the fuel level in the fuel bowl is at the proper level as specified in the shop manual, and the float system is working correctly. Carb floats – which are supposed to “float” – sometimes get holes in them and they sink instead, or the mechanism sticks.
Yeah, its better now. I think it’s Oxygen sensor could use some attention now, but at least it won’t drain me of my life savings just driving it around.
Well my older brother(rest his soul) fixed a 307 with the electronic carb-he rebuilt a standard Q-Jet and put it on there,dont remember the exact Model year-but the neighbor who was a GM man,was happy with the result-Kevin P.S. I’m not a GM man,but I actually liked a Q-Jet,wonder what this car would do if you put a TBI and 'puter on it? I remember how much better the Chevy 4WDs did with this setup-Kevin