I recently reacquired an '80 hatchback I owned two years ago and have made it my daily drive for a while. I know at one point when I had it the first time, I got as much as 25 mpg on one tank which I think is very respectable. Not sure what has happened to it since I had it last, but I filled it up tonight and I was very disappointed. Only got about 12 mpg. Granted, the weather is a little colder right now, but I would hope it would get mid to upper teens anyway. It has a new timing chain and gears and I think it's possible that the distributor isn't adjusted correctly or could possibly be off a tooth or two. I need to check that and also make sure the vacuum advance is working properly. The carburetor will need attention as well. I know it has been replaced although I'm not sure when. May need cleaning, adjustment and a new fuel filter probably wouldn't be a bad idea either. It's not idling right. At a stop, it's hovering around 500 RPM and is a little lumpy. Also noticed a little pulsing or surging around 50-55 MPH. The wires are in good shape, plugs were just replaced, cap, rotor and PCV valve are okay, air filter and breather filter are new, has fresh oil and fresh coolant.

I'm trying to think of other things I can check that could be causing this problem. Not sure if there's any vacuum leaks, but it looks like most, if not all, of the vacuum hoses are original, so they may be on their way out. Then there's all those little check valves. Could they be an issue? Need to check the tire pressure as well. That could even make a difference. If anyone can think of anything else I should look into that could be causing the poor gas mileage, I'd appreciate your suggestions. Thanks.

Scott