Rough starts when engine is warm and fuel is 1/4 tank or lower

[Dawnnorton]

Hi everyone!
I drive a 2006 4.0 with 78k miles on it. Have had problems here and there but nothing too serious. But recently, I’ve had a problem that’s stumped everyone. The jeep runs fine, but if I try to turn it on while the engine is warm and the gas is at (or under) a quarter of a tank; it shakes viciously, makes an awful clunking sound, my rpms fluctuates, and I get a horrible gas smell. It literally feels like an earthquake inside my jeep. Sometimes it stops doing it after 5 seconds, sometimes I have to it off and wait 3-5 minutes. The check engine light will pop on as well, but as soon as I fill it up the tank completely, the light will turn off and start completely fine. Hopefully one of you can help me since nobody else can!

 

[Daryl]

Check for codes and let us know what they are.

 

[Dawnnorton]

Check for codes and let us know what they are.

The code it threw was P0174 I believe, and on the scanner it said O2 sensor bank 2 if I remember correctly. My boyfriend replaced it, and still having the issue, a guy I know who is pretty good with jeeps believes it is a vacuum leak somewhere but we were not able to find one.

 

[TJ4Jim]

The code it threw was P0174 I believe, and on the scanner it said O2 sensor bank 2 if I remember correctly. My boyfriend replaced it, and still having the issue, a guy I know who is pretty good with jeeps believes it is a vacuum leak somewhere but we were not able to find one.

You will need to confirm what brand sensor he used for a replacement. If it was not a NTK sensor it should be replaced again. Our Jeeps do not play well with any other brand. The raw gas smell could be the computer trying to richen the mixture when the sensor is showing a lean mix.

 

[RMETeeJay]

Have him check the fuel pressure at the rail.