Hi guys,

My 2007 outlander dies after idle hunting. The code shows P0171 and P0174 then P2197 and P2195 after cleaning the lean codes. The auto shop identifies vacuum lean somewhere around the intake. After fixing the leak and replacing the two front o2, the car is running with a rough idle at 650rpm (shakes the entire car with uneven power output if the shift is on D or R) and random misfire. Codes are P0171, P0174, P0300, P2197, P2195. The short-term trim increases to 25% all the time after getting into idle. Once rpm rises, the trim runs fine. Air-flow is 3.x gal at 650rpm. EGR step is set at 4 steps during idle.
The fuel pump is running but neither the auto shop nor I have the tool for checking the fuel line pressure.
Any idea or experience?

 

possible MAF contamination? thinks it is getting more air than it is due to a coated wire? or do I have that concept backwards? airflow makes the wire colder and the ECM measures the amount of amps to heat it back up, so it thinks there is more air flowing and it trims rich to balance what it feels is too much air? too rich can gum up the works at low idle but when your at higher idle the fuel is burnt off easier? I could have all that backwards but a can of MAF spray is only $5

 

Thanks. I have it cleaned this afternoon, but no luck. Nothing is affected.

The car only runs rough when the computer is trying to push the rpm to the minimum, 600~650, and the trim goes from 0% to 25% as the rpm drops.

The O2 sensors go between 0 to 1V, but during idle they only stay at about 0.04V (for the front) and 0.02V (for the rear).

 

Wow, that does indeed sound like a stuck sensor. The rear should show lower than the front and the front should oscillate between .1 and .9 to keep from overloading the cat with fuel. The ECM is supposed to alter the pulse width to the injector based on that input and the MAF + PPS (Pedal Position Sensor).

They're such a pain to change. Last time I did one, I stripped out the stupid hole and had to get an insert, then re-tap the hole. Soak that thing with 'loosening oil' I use Kroil. Good luck, hope it fixes things.

 

The rear O2 is indeed lower than the front, but they only oscillate during driving NOT idle at all. The two front O2s have been replaced when the intake was taken off for the vacuum leak.

I can hear exhaust leak but not sure which part and might try to find where is leaking first.

 

Hey, did you find a solution for this issue? I'm having exactly the same problem, same error codes. Both upstream O2 sensors replaced and the check engine light is still on. Thanks a lot.

 

Mine cause was a vacuum leak from the gasket of the intake manifold.
BTW, after fixing the manifold leak, the shop hooked the hoses up wrong that the idle doesn't die but still ran rough.
The dealer found this issue during the visual inspection.

Definitely check the vacuum leak first.

 

Thanks a lot!