1994 chevy cavaliar

1994 cavaliar 4cyl with 207000 miles .Has a strong miss on startup even if it been running all day.only has a miss for 1 0r 2min then clears up runs fine only has a miss when below freezing this started last winter toward the end and cleared up for the summer i guess i was hoping problem was fixed, replaced plugs ,wires ,fuel filter still has a miss also not sure if related but the collant seems to bubble up like it gets a rush of air in the collant resevoir when the car get shut off.

forgot to mention i put some heet (water remover) in the fuel just in case there was water in the fuel no change .could it have something to do with the winter blend of gas

You did a great job to get that many relaible miles on a Cavalier. At this mileage, may things could cause your problem, but water in the gas is a likely one. The rush of “air” through the coolant would be a separate problem and could be an internal leak in the head gasket (we hope not); in any case you should get the car checked out by a competent mechanic. Try a water remover or gasline antifreeze first.

Put some more in the next time you fill up. It may take a few hits. That may not be it, but it could be and it is cheap to try.