Q: Rough Idle

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My fiancee's 02 galant es with a 2.4L is idling really rough and getting hard to start. It will try to crank then after a couple tries it finally does. Once it starts is idles really rough. I've replaced the IAC and the TPS what else could this possibly be causing this ?

My car has 137000 miles.
My car has an automatic transmission.

This may also be caused by other things such as low fuel pressure or leaking or intermittently working fuel injectors. When the fuel pressure is low, it will fail to bring the correct amount of fuel pressure to the injectors causing a lean fuel condition which may cause a rough idle. The same is true when the injectors are dirty or do not have the proper voltage running to them. To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose your rough idle firsthand. Best of luck.

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