I have a 2002 Pontiac Sunfire 2.2 liter OHV. I'm having an intermittent problem with power loss, rough idling, and engine noise fluctuation. This is usually only a problem at low to closed throttle positioning and usually clears up after advancing the throttle. Almost feels like the engine is being choked and when it does clear up, it is an instant gain in hp and will run smooth for a while, then the problem will reoccur until advancing the throttle again. I checked all plugs for fouling, all presented normal wear. What could this be?

Chrysler Sebring Questions - Car running very rough ...

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CarGurusMar 27, 2011 - It seems after car gets to a certain temperature it runs very rough. ... 2011 at 12:16 PM about the 1998 Chrysler Sebring 2 Dr LXi Coupe ... it.one day it washot out and it was running sluggish with rough idle.and ... I changed the altnator and battery its runs like its brand-new.now ... 2002 Chrysler Sebring LXi.

Chrysler Sebring Questions - Engine Power Loss After Car ...

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CarGurusNov 3, 2011 - Engine Power Loss After Car Is Warmed Up - Major loss of power after car has ... When vehicle is cold runs ok, sometimes a little rough but not bad. Full power. Allowed vehicle to run for over 45 minutes last night at idle, died on its own, car sat approximately 20-30 minutes. ... 2002 Chrysler Sebring LX.

* Chrysler Sebring/200 Convertible Club * • View topic - Rough ...

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Dec 29, 2006 - 5 posts - ‎3 authors
However, the vehicle still suffers from rough idle under certain conditions: ... been resolved (I don't think he noticed that it happened only when warm though). .... The test will tell you its general condition without having to dig it out of the fender, ..... Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group rough ...
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May 24, 2010
Low idle rpm
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Mar 8, 2007
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Possible causes
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Faulty Mass Air Flow (MAF) sensor
My bet would be dirty fuel injectors, Try putting fuel injector cleaner in your tank next time you fill up.

Change O2 Sensor number 2 which is down stream after the cat. Low voltage during power enrichment sensor 2

Check Mass Airflow sensor and O2 sensors

Is the wiring good going to the O2 sensors? Maybe just look the car over and see if you have any bad grounds. They can do weird things. Could be a bad ICU.

Sure sounds like a typical case of dirty/contaminated fuel....or a broken vacumn supply hose around the intake manifold area, in neutral let it idl;e and look and listen for a hissing sound, or a broken black rubber hose.
Also have the computer scanned for any possible codes.
Another thing to look at is the catalyctic converter, put a vac. gauge on the engine and see if the vac drops to almost zero...indicating a plugged cat.

BROKEN VALVE SPRING WOULD BE MY GUESS.

Sounds like you may have lost oil pressure. Could have engine damage, Have you had a service center perform a diagnosis’?

sounds like you have engine coolant burning in cyliders and white vapour comming from tailpipe.checkyour coolant reservoir for level.also check your oil and make sure it is not milky color and brown like oil should be.2.2 L blow head gasket and runs rough.please rate this good luck.

Are you certain that the engine is getting fuel? If not, then you will have to verify that there isn't any blockage in the fuel system to prevent the fuel from reaching the engine. If fuel is reaching the engine, try the following
1. Check compression values for each cylinder.

2. Inspect electrical circuitry in the distributor assembly (slack wires, broken wires, dmaged rotor etc)

3. Check to see if the timing belt was not severed. This belt transmits the drive from the crankshaft to the camshaft. If the belt ius severed, the camshaft cannot rotate in order to open the valves