2001 Jeep Cherokee poor gas milage - rough idle

[quote:0e0ce2569f="jeeper01"]Engine Performance problem
2001 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 54000 miles

I have rhe exact same problem as Jeeper2001. I have changed the spark rail . plugs, and checked injectors. i have not changed O2 sensorsi or cat. convertor.[/quote:0e0ce2569f]

Hello,

Well, to make it easier and so we don't have to spend time searching for the problem the jeeper2001 has could you please post the problem you are having.

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i used to have kinda the same problem it would idle really rough and hitch really bad going down the road had to change the TPS (throttle position Sensor) and the upstream oxygen sensor (the one up before your cat.converter. hope i was of some help here.

[quote:ca0935a7f1="jeeper01"]Engine Performance problem
2001 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 54000 miles

my 4.0 starts fine but after it warms up it idles so rough that the exhaust rattles,also gas milage has gone way down. engine lt. says cyl. 3 missfire . I have changed the spark rail . plugs, and checked injectors. replaced fuel pump. i have not changed O2 sensors . the drive rod for the oil pump and camshaft position sensor was recently replaced by a shop,so i assume the timing is ok. i took the cat. converter out and it is ok.[/quote:ca0935a7f1]

Ok,

Check for good spark it should be Bluish/White. Check IAC (Idle Air Control Valve), check compression fuel pressure and fuel regulater.
check for vacuum leaks.


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