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-   -   p0174 A lean air/fuel mixture has been indicated ?? (http://www.jeepgarage.org/f203/p0174-a-lean-air-fuel-mixture-has-been-indicated-20440.html)

LimitedStyleJeep 03-18-2011 12:36 PM

p0174 A lean air/fuel mixture has been indicated ??
 
Need some help here with my bro 01 GC..

Recently his motor sounds like it lost a cylinder and has been running rough..

Pulling the codes from the dash indicated p0174 A lean air/fuel mixture has been indicated by an abnormally rich..

Anyone know what could be the problem? Or where to start

Scottina06 03-18-2011 12:39 PM

Re: p0174 A lean air/fuel mixture has been indicated ??
 
4.0 or 4.7?

Frango100 03-18-2011 10:14 PM

Re: p0174 A lean air/fuel mixture has been indicated ??
 
Problem could be a vacuum leak, fuel pump or filter, O2 sensor.
Have the fuel pressure checked at the fuel rail and check for any vacuum leak.
If you have an OBD2 scanner, you could compare the O2 sensor outputs to see if there is any discreapancy with one of the sensors.

LimitedStyleJeep 03-19-2011 12:02 PM

Re: p0174 A lean air/fuel mixture has been indicated ??
 
Quote:

Originally Posted by Scottina06 (Post 378291)
4.0 or 4.7?

4.7

Scottina06 03-19-2011 01:45 PM

Re: p0174 A lean air/fuel mixture has been indicated ??
 
have him check the coolant and oil. Is it running hot or anything like that? See if he's losing any coolant or there is coolant in the oil. If nothing there...he may want to have the cylinders pressure checked. Could also be a bad 02, plug etc.

2005JGC 03-19-2011 10:18 PM

Re: p0174 A lean air/fuel mixture has been indicated ??
 
all great responses!

also, consider that chryslers will throw lean codes with a misfire. When a cylinder doesnt fire, your cylinder turns into an air pump, so instead of O2 and HC converted to exhaust gasses you get straightup O2 and HC in the exhaust from that cylinder, so your 02 sensor sees too much oxygen and you get a lean code.

This can happen without a misfire code if your adaptive numerator has not been set (likely if you have not driven the vehicle much or at all following the repair and you had your battery discocnnected). To set the adaptive numerator accelerate at approx 3/4th thottle to about 35mph (with the gear selector in like 2nd) and let off the throttle, allow an engine brake for 10-15mph and do it again 5-10 times. After doing this if its misfiring you will get a misfire code.

That being said it could be ANYTHING that could cause a misfire, coil, plug, injector, cylinder integrity, vacuum leak, an unplugged coil or injector ;)

Good luck


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