Car does not move right away when gas pedal is lightly pressed and once the pedal is released the car idle rough then back smooth. It's running excellent but rough when gas pedal is pressed and releas

did you tune it up at all , do u have a ck eng light on , do u have a vacuum leak this would cause you symtons

To begin with, is your "check engine (CE)" light on? If it was on and now its not, you need to replace the bulb. If CE lights is on, find out the codes before doing anything. If bulb is good and "CE" does not come on, begin with: (1) gapping spark plugs, (2) replace spark plug wires (if haven't changed them within the last 2), then the coil. If your Cinco is still idles rough, adjust gas pedal until idling smoothly. If this still doesn't help, replace your two oxygen sensors. If still running rough, the converter. After doing all this and problem is still present, take it to a mechanic you trust.

Does it have any power when you start moving? I've seen a lot of plugged catalytic converters. You may want to have an exhaust back-pressure test done.

Check the help links related to this problem.Click the link below to go through its troubleshooting procedure :-----Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.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 dies when gas pedal is pressed? http://schematicsdiagram.blogspot.com/2011/12/car-dies-when-gas-pedal-is-pressed.html
--------Pushing on the gas pedal, but the car slows down? Gas pedal to the floor and the car slows down?

http://technoanswers.blogspot.in/2012/02/pushing-on-gas-pedal-but-car-slows-down.html

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After replacing brake rotors and pads, brake pedal remains on floor? http://technoanswers.blogspot.in/2012/02/after-replacing-brake-rotors-and-pads.html

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accelerator pedal sensor? http://technoanswers.blogspot.in/2012/02/2009-chevy-impala-accelerator-pedal.html

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For rough idle issues and problem troubleshooting,go through the help links provided below :----- van idles rough?

http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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will not idle when cold?

http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html

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runs lean and idles rough?

http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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This will help.

Thanks.

Try increasing the idle speed. If you don't know, this is how to do it.
Open the bonnet and ask someone to push and release the gas pedal a five second intervals.
Observe which part is moving.
Yo will see a small adjustment screw on that lever. You will understand that by adjusting the screw you can increase the gas supply to the engine.
Slowly rotate the screw while the engine is running. (If the engine doesn't run in idle state as you have explained, ask someone to keep the pedal slightly pressed. After increasing the gas supply, ask the person to release the pedal).
Adjust it further to get a smooth running condition at idling.
Also check whether air cleaner is blocked.

• does the engine miss? bumps is a rythmic pattern?
• an engine miss will appear to diminish at higher rpm due to centrifical force.
• other possible problem broken or flat motor mount.
• is the idle rough in reverse?
• if not
• open hood
• start engine
• Left foot on brake (hard)
• start engine
• watch engine as you select drive
• still holding brake with left foot / throttle gas with right foot
• does engine dramatically move?
• if so replace motor mount on offending side
• if not possible engine miss or transmission problems

My quest 2004 idle below 500, start up then off, have to start couple times when the engine is cold. when i pushed the gas pedal, it smells gas.

There is a throtle adjuster right behind the carb. You can adjust it with a screw driver. If you are not sure where it is, just have someone press to gas pedal and you will see it move. RPM's at idle should be around 1,000 when it is idle once it has warmed up. Once that car warms up the choke moves back in and the car is probably stalling because it is not running enough RPM's.

Just trowing some suggestions out there, but, I would check the idle air control valve (solenoid) or the throttle position sensor. If they check out then my last guess would be the map sensor or the vaccuum to the map sensor. Hope I was able to help. Best wishes.