Car stalls

2000 Ford Focus SE, 4 cyl - A few weeks ago engine light came on. Check the codes, it was for a mis-fire on 2nd cylinder. Found that the plug wire was not fitting correctly. Re-set, but it came coming off. Due to age and not sure of how old plugs or wires were decided to change out. All plugs and wires were replaced with new ones. The old plugs were set at a gap of.045, yet the specs called for.052-.056. New plugs were set to specs. Codes were cleared.
But then began to experience the engine dying every time the vehicle was put into park. No new codes issued. This behavior was not consistent, as the dying occurred at certain runs and then would not occur at all. Has happen with air on, then with air off. Has happen when decreasing speed to a stop light.
Pulled plugs again and reset the gap to the original setting thinking that maybe there was a connection. But the problem still exists and no new codes have been issued.
Wanting to find a direction to fix the problem. Currently at a lost due to the inconsistent behavior.
Sometimes it does not happen at all and will not die, then shut vehicle down and restart it, it will start up but quickly stagger and die. You can force it to maintain by pressing the brake and gas and jump shifting to drive. Then other times it starts up, runs fine never showing a sign of issues.

Car is a deisal wouldu lose presure over acouple of minets

I have a pressure tester but not sure where to connect it to the system. I do not see a port between the fuel filter and fuel rail. Is this the only place to test the fuel system pressure? Or is there a place underneath the vehicle? It has he 2.0 Split-port 4 cyl motor.

I recently bought my car from a used car dealership and their product is usually pretty reliable, and affordable. I haven't heard any complaints from them. However, I have had it for about a week and haven't had any problems until yesterday. I was on my way home from work, and I was getting onto the highway which looped down from an intersecting main road above. I was doing approximately between 40-50 mph. On the on-ramp itself. And about 3/4 of the way around the turn, the car basically shut off. Now, I say basically, because the radio was still on, the lights were still on, I was still moving, but it sounded like the engine went to an idle, and shut off. I pulled over, sat with it in drive for a minute because I didn't want to break anything, and then decided that I wanted to put it in park and turn the ignition to off. After I did that, I noticed that the check engine light, the oil light, and the battery light were all on. However, the car started right up and got me home with no other problems. I called the dealership as soon as I got home, and they said the old, 'Call back if it happens again, ' bit. So, on my way home from work tonight, it happened in the same exact spot, and then AGAIN on the off-ramp. I haven't gone on a left entrance or exit ramp yet, so I don't know if it happens when I turn the wheel both directions, but it does seem to be when the wheel gets to a certain point, with addition to a certain speed. I don't know if there are wires loose, and the wheels are hitting them. Or the battery cables are loose, I haven't looked under my hood because I don't know what to look for. I am 20 years old and my Dad is also uncertain of what it could be. I am going to call the dealership back tomorrow and see if I can bring the car in and have them look at it. I am asking on here, if you have heard of this problem before, or any clue as to what could be shutting my engine off.

I am unable to locate the port. I assume by you saying the Fuel Rail Manifold that it is not on the fuel rail itself, but yet there is nothing else that looks like a port to connect a tester too. Can you tell me which side of the engine it is on and what it is close too? Driver's side or Passenger's?

Ok, I saw that thing and wondered if that was not it, but was not sure how to access it, makes sense now. I appreciate the assistance. Could it be possible that this could be something other than the fuel system. Just the inconsistant behavior of it is what makes me ask. Like last night, I set the sprak plugs back the specs and then took it for a spin. I never had any problems until I put it into park. It died immediately. I was able to start it but each time it stalled out. Was able to get it going again by holding the gas down along with the brake and jumping it into drive. But then later after shutting it down again. It started up (no stalling) ran fine and didn't have any issues. So if it is the fuel system, could it be that the fuel pump is going out?

Engine Performance problem
2000 Ford Focus 4 cyl Automatic 106000 miles

my engine is stalling when I come to a full stop. It also has a hard time accelerating and going up hills. I feel it is probably the fuel injector, or possibly the spark plugs. When check engine light went on, and i've take out the spark plug connector and found as least 1/2 cup of water inside. I took out the water and the check engine light went off, (maybe went off then I disconnected the battery?) But I still have the same symptoms. I've gotten this car used last year, and dont know if I should change timing belts or whatnot

Will do a diagnostic check. As for coolant, it was very low when I got my car a week ago (was out of state for 3 months and a friend drove it), so I filled it to nominal amount, and so far it seems to be the same.

I'm sorry, i'm still getting into the car talk lingo here, what does the "compression test" test?

I have been trying to do what was in the first answer, but lacking tools and time, I am taking the vehicle to a mechanic to have it tested. Hence the reason for my further inquiry, as needed to know what more could cause this issue prior to some shady mechanic painting some horrid picture costing hundreds. Just trying to get as much information as possible. No expectations of a magic wand, but just testing the fuel pressure does not explain to me a direct possible cause. Does it? I have no clue, which is the reason I came here to ask and learn! Once I have it tested I will follow up with a response.