car only starts when gas pedal is pressed?

It sounds like there might be something wrong with your idle air control valve. Does your exhaust smell excessively of gasoline?

At this time your explanation makes this look like a faulty idle air control valve which is mounted on the throttle body. I also recommend if it is close to time for a tune up then go ahead and install new plugs and wires. It always helps to do a fuel system service as well.Its possible that fuel pump is got weak and loosing pressure.

You might need a new fuel pump. There is not enough fuel getting to the engine to start it, so if you press it than its enough.

Also see this more help solutions:----

Car dies when gas pedal is pressed?

http://schematicsdiagram.blogspot.com/2011/12/car-dies-when-gas-pedal-is-pressed.html

Car won't start without hitting the gas pedal?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-without-hitting-gas.html

Complete loss of brake pedal then all gets normal?

http://repairhelpcenter.blogspot.com/2012/01/complete-loss-of-brake-pedal-then-all.html

Car loses power while acceleration?

http://schematicsdiagram.blogspot.com/2011/12/car-loses-power-while-acceleration.html

How exactly the Vehicles Accelerator Cable works?

http://repairhelpcenter.blogspot.com/2011/11/how-exactly-vehicles-accelerator-cable.html

How exactly Vehicles Accelerator Pump Diaphragm Works?

http://repairhelpcenter.blogspot.com/2011/11/how-exactly-vehicles-accelerator-pump.html

Acceleration lag problem?

http://repairhelpcenter.blogspot.com/2012/01/acceleration-lag-problem.html

---------

The car will not start?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-start.html

-----------------

Car will not crank?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-crank.html

-----------

Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

-------------

How to troubleshoot car battery?

http://schematicsdiagram.blogspot.com/2011/06/how-to-troubleshoot-car-battery.html

-----------------

How to test starter solenoid?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-starter-solenoid.html

--------------------

How to test cars starter?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-cars-starter.html

How to replace starter in car?

http://schematicsdiagram.blogspot.com/2011/06/how-to-replace-starter-in-car.html

-----------

car will turn over but will not start?

http://technoanswers.blogspot.com/2011/05/car-will-turn-over-but-will-not-start.html

-----------------

Car wont start?

http://howtobyme.blogspot.com/2011/10/car-wont-start.html

Engine will not start?

http://schematicsdiagram.blogspot.com/2012/01/engine-will-not-start.html