1995 Suzuki Esteem Sputtering

Hi digitalexclusion and TY for the donation

Do below before you replace the fuel pump might not be it

Check and Test:

Oxygen sensor
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

At your present mileage replace the oxygen sensor if it has been done before.

You need a DVOM to test the O2 sensor

Attach the positive lead of the voltmeter to the oxygen sensor's output wire while it is attached to the car's ECU. One can use jumper wires to gain this access as well. The negative lead of the voltmeter is to be attached to the ground or on the engine block or an accessory bracket.

Set the voltmeter to look for 1 volt DC. In cold, the engine should output between 0.1 volts to 0.2 volts while when the engine has been running for over 20 minutes, it would be warm and the output should fluctuate between 0.1 volts to 0.9 volts.

Some cars use either 2 or 3 wires instead of 1 wire. In these cars, the heated sensors will give an output of 12 volts on one lead, ground on the second lead and the sensor signal on the third lead. In these cars, when you turn the key to " œON' but do not start the engine, there will be a change in the signal.

This is a simple method of testing if the oxygen sensor is working properly or not.

This way, one can ensure that the oxygen sensor in one's car is in proper working order and if not, one can take the necessary steps to change, replace or repair it.