1997 ford ranger xlt with a 4.0 v6 2wd. Recently started getting a hesitation. I immediately made an appointment with my local firestone. I dropped it off. 4 hours later they called me and said that cylinder 4 is low compression and that is why I am having a hesitation. Where should I go from here? Thoughts? They said they hook their computer up to the truck and that's what told them number cylinder 4 was low on compression....

 

It's a long shot but make certain the spark plug in cyl. #4 isn't rattling loose. It can happen.
Do a dry then a wet compression test. The wet test can reveal bad rings.
Do a single cylinder leak down test to any low comp cylinders. This can reveal bad valves.
Smell your coolant. Exhaust smell reveals a bad head gasket.

 

I performed a combustion leak test and the ranger passed, Next is compression test, then cylinder leak down test...

 

I want to perform a cylinder leak down test on my 4.0 liter OHV. What is the best way of going about to perform said cylinder leak down test? How do I go about finding TDC for each cylinder for compression stroke?

 

I've seen charts for engines which show the valves' positions as you turn the engine manually-starting at #1 TDC.
Alas, I don't even know what these charts are called.
So, in the absence of said chart, start at #1 TDC and turn the engine through its firing order.
Since the plugs will be out you can CAREFULLY put a slender screwdriver into the hole and gauge when the piston reaches the top.

Then fit air into the suspect cylinder. Listen at the TB for leaking intake valves and at the exhaust pipe for leaking exhaust valves.

 

I guess they weren't fibbing? Advice? Compression test and leak down test?