my 2000 nissan frontier v6 will run fine, but it struggles to turn on unless I step on the gas pedal and pump at it a bit while starting the car. on a second attempt to start the car, it often will start without giving it a little bit of gas. I am thinking of starting with a compression test to check the health of the engine. I also suspect the throttle position sensor or the idle air control valve. The car runs fine once it is turned on, stable idle and no check engine light.