The car is idling,one battery terminal is disconected,the idling goes up and down,its not as smooth as before almost to close off intermittantly.what could cause this type of idling.

Make sure generator drive belt is good and has proper tension. Everything off, use a digital multimeter at generator bat terminal. Note the reading. Take second reading at the battery terminals. The two readings should be very close. If much difference have to check that wiring circuit.
Any applicable trouble codes relating to charging system? How old is your generator? Your generator is computer controlled.

Possible bad Idle Air Control valve. (same issue with my mustang.)
Replaced the IAC and everything smoothed out perfect.

could be a vacuum leak at a hose or gasket. with the engine running spray a little carb spray at the intake manifold area. if the idle picks up you are close to the vacuum leak. dont spray on the exhaust manifold area, be careful

did you replace the plugs,wires? a bad plug o wire can cause a bad idle. Vacum leak could do it too.

Its a faulty idle air control valve.You can take it off and clean it using a non-chlronated brake cleaner and a wire brush or and a scraperor you can replace it with a new one just make sure to reset the computer afterwards by disconnecting the ground cable on the battery for 30 seconds then start it.

It sounds like the battery was not disconected long enough to fully reset the computer.
Loosen and remove the neg. battery terminal, wait about 20min and replace the terminal. Things should
return to normal. Hope this helps. Good luck

Check your wires and spark plugs. If it is carburated engine check your air filter and vacum hoses.

You might try testing the tps. It may have a dead spot at the high end of the throttle opening. Make sure the resistance continues to change as you open the throttle all the way.

Throttle Position Sensor

Operation The throttle position sensor is a rotating type variable resistor that rotates with the throttle body-s throttle shaft to sense the throttle valve angle. As the throttle shaft rotates, the throttle angle of the sensor changes and the ECM/PCM detects the throttle valve opening based on the TPS output voltage.
Removal & Installation

1. Disconnect the negative battery cable.
2. Disconnect the sensor connector.
3. Remove the sensor retaining screws. Remove the sensor from its mounting.

To install:

1. Installation is the reverse of the removal procedure.

Testing 2.4L Engine

1. Disconnect the sensor connector.
2. Measure the resistance between terminal 1 (sensor ground) and terminal 2 (sensor power).
3. Specification should be 3.5-6.5 kohm.
4. Connect and analog ohmmeter between terminal 1 (sensor ground) and terminal 3 (sensor output).
5. Operate the throttle valve slowly from the idle position to the full open position, and check that the resistance changes smoothly in proportion with the throttle valve opening angle.
6. If the resistance is out of specification, or fails to change smoothly, replace the sensor.

2.7L Engine

1. Disconnect the sensor connector.
2. Measure the resistance between terminal 2 (sensor ground) and terminal 1 (sensor power).
3. Specification should be 3.5-6.5 kohm.
4. Connect and analog ohmmeter between terminal 2 (sensor ground) and terminal 3 (sensor output).
5. Operate the throttle valve slowly from the idle position to the full open position, and check that the resistance changes smoothly in proportion with the throttle valve opening angle.
6. If the resistance is out of specification, or fails to change smoothly, replace the sensor.

1. Disconnect the sensor connector.
2. Measure the resistance between terminal 2 (sensor ground) and terminal 1 (sensor power).
3. Specification should be 1.6-2.4 kohm.
4. Connect and analog ohmmeter between terminal 2 (sensor ground) and terminal 3 (sensor output).
5. Operate the throttle valve slowly from the idle position to the full open position, and check that the resistance changes smoothly in proportion with the throttle valve opening angle.
6. If the resistance is out of specification, or fails to change smoothly, replace the sensor.

3.5L Engine

1. Disconnect the sensor connector.
2. Measure the resistance between terminal 3 (sensor ground) and terminal 1 (sensor power).
3. Specification should be 3.5-6.5 kohm.
4. Connect and analog ohmmeter between terminal 3 (sensor ground) and terminal 2 (sensor output).
5. Operate the throttle valve slowly from the idle position to the full open position, and check that the resistance changes smoothly in proportion with the throttle valve opening angle.
6. If the resistance is out of specification, or fails to change smoothly, replace the sensor.

Remove Negative terminal first, then positive terminal. Battery will have some type of tie down or block at base with a bolt you will have to remove. Remember how it goes back together. Remove battery.
Install new battery and tie down or block. Install Positive terminal then Negative terminal.
Remember to never touch both Positive and negative terminals with a metal object (ie..ratchet, wrench etc) this can cause injury and/or permanent damage to a new battery.

Disconnect the negative battery terminal, using a 12v test light put one end on the battery terminal put the other end on the cable if you have a draw the light will light up, go threw and disconect one fuse at a time until the light goes out, notice the fuse you pull out when the light goes out that the circuit that you have your short or draw in good luck