1998 Volkswagen Jetta Fuel Pump

Its a gas.

I replaced that about 3 weeks ago, because the check engine light came on and it gave me that code about the coolant temperature sensor. I don't know what else could it be.

After I replaced it, the code went away and it never came back anymore as of now that I know of.
The cranking was good when I try to start it, I did notice a little bit of black smoke coming out from the exhaust. But it then went away.

I havnt had the chance to do the fuel pressure test, but I will soon. Maybe tomorrow.
I put in new spark plugs about two years. I got those bosch fusion, which they were expensive. I replaced the plug wires too. I would have to take one out to see what the burning condition is, it shouldnt be that bad.
I did had some problems before with my idling because it was a little high. So I cleaned the throttle body and replaced the IAT sensor and it stopped doing that.
Last year the long block got replaced. I put a new one. I'm trying to think whatelse have I changed. Well, I will let you know if I can think of anything else.
I really appreciate ur help.

U mean like valves and all that kind of stuff? Is a single cam with 8 valves 2.0L.

It has already 116000, but last year the engine was replaced. Just the long block. I did recently start to notice some coolant coming from the weep hole on the water pump. I replaced the water pump about 2 years ago. Do you know what could have cause it to start breaking down so fast? I have a feeling the coolant has corrosion in it. I'm actually planning on buying a new water pump with the housing and drain all the coolant, put new in it. I also did notice that when I put the ignition in on position and listen to the fuel pump, I dont hear anything. When I start the car I hear it working.