Idles okay, runs rough when gas applied

Clogged fuel pump., bad gas. Clogged fuel filter or injector (s)

Sometimes that's caused by a vacuum leak near the manifold area.

Sometimes air in the coolant will cause an idle problem. Air will keep the air temp sensor from sending proper info.
Hope this helps.

Rough Running Engine - James on Engines #2 - Bell Performance

https://www.bellperformance.com/blog/rough-running-engine

Apr 21, 2015 - When diagnosing an engine with a rough idle, there are certain things that must be ... If the problem does not reoccur, the codes will be erased by the computer. ... when accelerating the vehicle, which causes a higher fuel demand. .... it was water in gas...added added Gas LineAntifreeze/Water Remover.

simple test for a vacuum brake booster
star and run the engine at idle without applying the foot brake
if it gets worse when the foot brake is applied , it is a vacuum leak in the booster ( replace the booster )
otherwise check for failed vacuum hoses including under dash control lines , vacuum leak at the manifold or EGR unit

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.

For this types of problem,there are few help inks to troubleshoot the problem.Click the link below to go through the troubleshooting procedure to resolve the issues :----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-----------van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html
--------------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Car still runs Rough after tune up? http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html
------------Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed? http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html
----------High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html
------------Engine Backfires? http://technoanswers.blogspot.in/2012/02/jeep-backfires.html----------- Nissan stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

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Nissan Pathfinder Backfires? http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-backfires.html
---------How to adjust rpm? http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
------------Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html
----------This will help.Thanks.

engine rough at idle only?
is the check engine lamp on?
remove egr valve
start engine to blow out carbon
check egr to see if there is carbon holding the valve open
clean valve
reinstall retest

sound like its missing
check sparkplugs wires and coil pack for fire if not that run a compression check

you have a bad injector, if you have A... as it states on the top of the motor 2.8, 3.1 L MULTI PORT and dies or idles really rough and the exhaust smells like strong gas. most likely you have an injector that has shorted or is shorting out and from my experiences usually after a road trip or using fuel injector cleaner or buying a used car. it will cause half the motor to not run or run poorly VERY POORLY or even burn out 1 injector fuse out of 2 under hard acceleration or idles but as soon as you touch the gas pedal dies. but only if it is a MULTI PORT fuel injected motor. ive heard you want to try and replace them with bosch injectors out of a 2.9l ford bronco/ranger. only attempt if you got the mechanical know how sometimes if not done right will leak gas because of the injectors being kinda different length. research before attempting.

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.