Running Rich and Lean at the same time

[BORDENCOMANCHE]

96 XJ with a four litre. For some stupid reason its running rich and lean at the same time. I can't figure it out for the life of me, it eats gas like theres no tomorrow. I replaced the feul filter and ALL IGNITION COMPONENTS. It gives me code 11, 12, 51, 52, and 55. Can't figure it out. The 11 code is for the CPS, but its brand new, less thank 400 kilometres on it.

 

Please help.

[mvusse]

Coolant temp sensor or O2 sensor? Usually burning fuel like crazy is caused by the computer staying in open loop mode.

[mvusse]

From the web via Google:

 

11 No ignition reference signal detected during cranking OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor.

 

12 Battery or computer recently disconnected

 

51 Oxygen sensor stuck at lean position (this may be tripped by a bad MAP sensor system causing a rich condition. If you get hot rough idle and stalling, especially on deceleration, accompanied by flooded engine and difficulty restarting, that can be a bad MAP sensor causing the O2 sensor to try to compensate. If you get poor cold driveability, stumbling and bucking, and acceptable warm driving with poor gas mileage (a drop of 10 mpg or more), that is usually the O2 sensor.

 

52 Oxygen sensor stuck at rich position

 

55 End of codes

[carnuck]

96 XJ with a four litre. For some stupid reason its running rich and lean at the same time. I can't figure it out for the life of me, it eats gas like theres no tomorrow. I replaced the feul filter and ALL IGNITION COMPONENTS. It gives me code 11, 12, 51, 52, and 55. Can't figure it out. The 11 code is for the CPS, but its brand new, less thank 400 kilometres on it.

 

Please help.

 

 

96 has a LOT of computer issues that sometimes need the computer replaced (I'd suggest a '97) to get them running right or re-flashed with the factory machine. Coolant sensor is another problem. Cam sensor is in the dist. Bad thermostat (too cold) will eat more fuel because it will switch back and forth from lean to extra fuel (like a choke is on)