Engine trouble - o2 sensors?

[jmurphy]

Hi,

My Jeep started running like crap today. Virtually no power to accelerate. Constant pressure on gas pedal results in a roller coaster of power: full, none, some, none. I can drive around at around 20 km/h but trying to accelerate past that is pointless.

Engine light is on and shows 2 codes: P0132, P0138. Both are for o2 sensors, upstream and downstream as far as I can figure.

Would upstream sensor failing cause this? Downstream sensor has failed before without an impact like this.

My interweb searching suggests I may have a clogged cat. Does that make sense with these symptoms?

2000 TJ 4.0 with a number of exhaust leaks and a cracked manifold. Fan clutch is also seized and leaking coolant at waterpump.

TIA,

Jonathan

[Enos]

Give your cat a couple of whacks and see if it rattles, they can break up inside and plug the exhaust.

IIRC, upstream O2 causes more problems than downstream.

[Cherokee Chief]

Cat test.
Drive vehicle and at the time when its acting up.
Push accelerator all the way down, push in clutch in or pop it in neutreal, if it reves up instantly Cat ok, if it acts the same and will not rev up cat bad.
Simple as that

Darren

[jer]

Upstream monitors your AF ratio and communicates with your ECU to make the fuel changes. The downstream is there to more so make sure the changes were done. If your upstream shits the bed, your downstream will be reading funky as well causing both codes. Another way to check if your cat is clogged. Remove the upstream O2 and take it for a short drive, see if your Jeeps power comes back.

[Donair]

Resurrecting an old thread here, but jmurph, do you recall what ended up being the fix for this?

I have same symptoms; wonky/no power, near stalling at idle. Seems to happen when I let Jeep warm up from cold before driving (normally I have a short commute and just hop in, start and go). I just had leaking manifold flange repaired a month ago as I had the same symptoms prior to exhaust fix, exhaust fix seemed to make misfiring like symptoms disappear but symptoms returned on drive home on Friday after work.

Seemingly of note, a month ago when symptoms first happened, it was during a snow storm and I had let jeep warm by idling in driveway. Fridays return of symptoms (a month after exhaust fix and no symptoms) was after ~10 minutes of commute driving during snow storm after I warmed jeep at idle in work parking lot. Otherwise I have not had symptoms. I have not otherwise warmed vehicle and I likely have not driven it more than 10-15 minutes at a time.

On/off key trick shows code P0132 & end on odo.

[The Garagemahal]

Front 02 sensors are the first cause of this , ( if you already did the manifold gasket )

[jmurphy]

Jan 31, 2016 18:11:42 GMT -4 The Garagemahal said:

Front 02 sensors are the first cause of this , ( if you already did the manifold gasket )

Yup. Mine was the upstream o2 sensor.

Replaced the sensor and it's run fine since then.

Jonathan

[Donair]

Thanks guys, gonna get that upstream O2 sensor replaced.