2000 Ford Taurus Jerks After Start
I would have the fuel pressure system checked. It may be something as simple as a check valve allowing fuel to drain back to the tank and not being at the fuel rail to start the car.
Try this....Listen in your gas tank and have someone turn the ignition switch to the on position, but not start the car. You should hear the pump run for a few seconds. If it does, then turn the switch off. Turn it back on and see if it runs for a few seconds. Do this several times before attempting to start the car. Then start the car. If the problem is not there, then running the pump several times got fuel up to your rail and it wasnt starving for fuel. If by some crazy way this worked, you will need to find out why the fuel is running out of the lines. Bad check valve at the fuel pump. You might can install a check valve in the fuel delivery line and not have to open the fuel tank.
If it is not a fuel pressure or delivery problem, then I would look at the IAC and the controls for it under a cold start condition.
Suggested Repair
Check fuel pressure and delivery. Prime the pump several times with the key on before starting; if the stumble disappears, suspect a fuel-pump check valve letting fuel drain back, and consider an inline check valve if the tank does not need to be opened. If fuel pressure is normal, inspect the idle air control valve and its cold-start controls.
Conversation Summary
A 2000 Ford Taurus with 68,000 miles starts normally after sitting but jerks or feels like it is cutting out several times for the first 15 to 20 seconds, then runs fine with no check-engine light. The fuel pump was replaced about a year earlier. The expert recommends checking fuel pressure and a possible check valve that lets fuel drain back from the rail, using a key-on pump prime test to see if the stumble goes away, and if fuel delivery is not the cause, inspecting the IAC and its cold-start controls.
