2004 chevrolet Impala 3.4L engine.
Replaced Ignition module, mass air flow sensor.
Question = Why do my car vibrate when I'm idled a light and it does not always start on the first start, i have to give it gas by stepping on the accelerator.
Answer: Code P0300 engine misfire will not be caused by a bad mass airflow sensor, so you wasted your money on that part. Most misfires are caused by a bad spark plug, plug wires or sticking / faulty fuel injector. Check those basic things first. A good scanner will tell you what cylinder is having a problem so you can concentrate on that one instead of just guessing at parts.
Rough idle, and hard starting may be from a leaking fuel pressure regulator. When they fail, gas goes into the vacuum line and causes a rich condition. That is why you have to hit the gas to clear it out and make it start and idle better. Check the 3400 fuel pressure regulator.
What else has to be removed so that I can replace the starter on a 2002 chevy impala 3.8 liter.
Not a thing! You can access the starter easily from underneath the vehicle and have no problem removing it from between the oil pan and subframe area. There may be a small plastic cover that has three small 10mm bolts that is covering the nose of the starter/flywheel area that has to come off, but that is very easy as well. Good Luck!
2004 Impala Vibrates- How to Replace Starter