Infinity g20 rough idle

Answer 1

Start with a full tune-up,replace O2 sensor,fuel pump,or also fuel pressure regulator and/or injectors.

OR...simply check your fuel injectors...simple simple simple

Testing and changing a bad fuel injector is very simple. Just unplug the plastic wire connection while the engine is running (push the plastic clip in on the back to release the lock), no change in the way the engine runs indicates that your injector is bad, a good injector will cause the engine to run worse when the electrical connection is un-plugged. Simply remove the 2 screws and the cover, spray a little lubricant around the base while you turn the unit (cresent wrench works great) to loosen/break the o-ring seal, then gently but forcibly pry/pull the old injector straight out. Spray a little lubrication (wd-40 works fine) on the new o-rings and and push/seat the new unit in place, replace the cap and screws and re-connect the electrical before starting.

Testing With a Multimeter/Ohmreader

1 Set your multimeter to check for resistance or turn on the ohmmeter.

2 Disconnect the wires to the injector.

3 Place your meter's leads on each of the two injector terminals. Read the meter display.

4 Check your service manual for your car's resistance number. Most fuel injectors have a resistance of between 10 to 18 ohms.

5 Test each injector. If any of the injector readings are higher or lower than they should be, you need to replace them.

Listening

1 Put a long screwdriver directly on the injector while the car is running.

2 Hold the handle up to your ear. You should be able to hear a rhythmic clicking sound. If you do, your injector is good. Hearing a clunk-clunk type noise means you have found your problem.

3 Hearing silence or unusual clicking patterns means either the injector, wires or plunger may be bad or sticking. You will either have to clean or replace them.