Overheating 2002 Taurus 3.0 single. We have flushed system, change thermostat and coolant. Heats up in slow traffic or stop, runs okay at speeds over 40. could the water pump be going bad?

Hello, I'm sorry that I have not responded to you sooner. I am recovering from some recent surgery and I basically slept most of the day yesterday. I'm also sorry that my information did not solve your problem. So, I guess it's time to pick up where we left off.
Well, it sounds like you have covered the basics requiring more advanced diagnostics.We need to determine why the problem occurred in the first place. Did the vehicle have some type of service done to it shortly before the problem started?If this is so, then what type of service was performed? If not, then we need to verify some information.
When one of my customers tells me that their vehicle is overheating, it's because their temperature light is on. This can be caused by a faulty temperature sensor. Therefore, we need to determine if the engine is actually overheating. First, lets look at the symptoms.
Signs of overheating usually include :
1. Rough running, unstable idle.
2. Loss of power.
3. Detonation (pinging) during acceleration.
4. Coolant boiling in the overflow tank.
If you are not experiencing any of these symptoms, then verify operation.
A cooking thermometer rated for at least 250 deg. F will work.
1. Tape the thermometer to the upper rad. hose near the thermostat housing.
2. Start the engine and let it reach operating temperature. (upper rad. hose hot)
3. If the fan comes on, note the temperature that this occurs.
4. Let the fan run until it shuts off. Note the temperature that this occurs.
If the temperature stays between approx. 210-230 deg. F, then the most likely cause is a faulty coolant temperature sensor. If the temperature does not go down when the fan comes on, then check the fan for proper operation.
1. Disconnect the electrical connector to the fan.
2. Turn the fan by hand. You should feel a slight drag.
If the fan feels loose and appears to "freewheel", then compare it to a new fan to determine if there is a difference. Replace as needed.
If everything checks out OK, then a restriction in air flow or a restriction in the system itself is indicated. Look closely at the front of the radiator. (or condenser) to make sure it's free of dirt and debris. You can also have the radiator tested for restriction by a radiator shop. If it turns out to be restricted, then the rest of the system will need to be chemically flushed. If you have the radiator serviced, then replace the cap with a new one (if it has one) or replace the overflow tank cap. I hope this solves your problem. If it doesn't, then leave me a post and I will try to work with you until it is solved if you want me to. It can be difficult when you can't actually see the vehicle that your trying to help with. Good luck to you. Hello, I'm sorry that I have not responded to you sooner. I am recovering from some recent surgery and I basically slept most of the day yesterday. I'm also sorry that my information did not solve your problem. So, I guess it's time to pick up where we left off. Well, it sounds like you have covered the basics requiring more advanced diagnostics.We need to determine why the problem occurred in the first place. Did the vehicle have some type of service done to it shortly before the problem started?If this is so, then what type of service was performed? If not, then we need to verify some information. When one of my customers tells me that their vehicle is overheating, it's because their temperature light is on. This can be caused by a faulty temperature sensor. Therefore, we need to determine if the engine is actually overheating. First, lets look at the symptoms. Signs of overheating usually include : 1. Rough running, unstable idle. 2. Loss of power. 3. Detonation (pinging) during acceleration. 4. Coolant boiling in the overflow tank. If you are not experiencing any of these symptoms, then verify operation. A cooking thermometer rated for at least 250 deg. F will work. 1. Tape the thermometer to the upper rad. hose near the thermostat housing. 2. Start the engine and let it reach operating temperature. (upper rad. hose hot) 3. If the fan comes on, note the temperature that this occurs. 4. Let the fan run until it shuts off. Note the temperature that this occurs. If the temperature stays between approx. 210-230 deg. F, then the most likely cause is a faulty coolant temperature sensor. If the temperature does not go down when the fan comes on, then check the fan for proper operation. 1. Disconnect the electrical connector to the fan. 2. Turn the fan by hand. You should feel a slight drag. If the fan feels loose and appears to "freewheel", then compare it to a new fan to determine if there is a difference. Replace as needed. If everything checks out OK, then a restriction in air flow or a restriction in the system itself is indicated. Look closely at the front of the radiator. (or condenser) to make sure it's free of dirt and debris. You can also have the radiator tested for restriction by a radiator shop. If it turns out to be restricted, then the rest of the system will need to be chemically flushed. If you have the radiator serviced, then replace the cap with a new one (if it has one) or replace the overflow tank cap. I hope this solves your problem. If it doesn't, then leave me a post and I will try to work with you until it is solved if you want me to. It can be difficult when you can't actually see the vehicle that your trying to help with. Good luck to you.