Well Leslie ,
Could be several things that make it rough.
"Water" out the exhaust or coolant out the exhaust ? Water is usually condensation every time you start and / or a byproduct of combustion.
Is it overheating? AND loosing coolant ? Does it run at what has been " normal " temperature range?
Diagnose one issue at a time.
A head gasket can fail in a few ways. The seal from the piston combustion chamber can breach to the outside leaking to the ground, the most rare. It could breach to the crank case or oil system, also under pressure and less common. It can breach to the coolant galleys pressurizing them with combustion gasses. Or it could get the the exhaust, and often but not always the result of overheating and a crack in he head casting.
Here is a quick check.
Starting with a cold motor start it and if there is pressure in 30 seconds when you release the radiator cap good chance it is breached to some degree. When I didn't have two extra nickels to rub together I ran back and forth to work with the cap loose and added water when needed.....for about a month until I saved. I don't recommend
that for new cars.
How low is # 3? More than 15% of the rest (65 as the rest are 110 for example).
If you have a way to hold #3 at TDC and apply air pressure WITH A REGULATOR AND DO NOT EXCEED THE NORMAL LOWEST ALLOWED COMPRESSION (warm engine coolant cap Off) and see if you get air out the radiator or exhaust
( you can put you ear to the tailpipe NOT RUNNING and listen like a sea shell.
Hope that helps.
Old school back to the shop.
Tom
