Well it sounds like you have a few different concerns here.
The left front is the most common area for the intake to leak. It will cause an external leak, running down the left front. ( did you see signs of this???)
It is possible if the intake was loose for the coolant to get into #1 cylinder intake port.
To verify that coolant is not getting into the combustion chamber through a head gasket or crack in the block or cylinder head. you can use a chemical tester called BLOCK CHECK. It is a blue fluid that changes to yellow in the presence of combustion gas.
You put some in a tester and it is inserted in the radiator opening. Then you let the engine idle. If the fluid changes from blue to yellow, you have a combustion leak.
The second way to check this is to remove all the rocker arms, so the valves will stay closed. Remove all the spark plugs and use a hose with a fitting that will screw into the spark plug hole. Use air up the cylinder and then look for bubbles coming out the radiator. Putting a tight fitting funnel in the radiator opening and fill it with coolant will allow you to see the bubbles easier.
This should not cause the engine to loose power around 2000 rpm though.
1st , What is the timing set at, and how did you set it?
2cd when this lack of power occurs, is it like running out of fuel, or does the engine start to miss/jerk feeling?