O2 Sensor help? P0136
Thread Starter
|
New User
Joined: Jan 2010
Posts: 8
Likes: 0
O2 Sensor help? P0136
Hey Fellas,
Got a couple of problems with my 2000 2wd XLT 5.4L with 120,000 miles.
I pulled two codes tonight and researched them both. P0303 and P0136. After reading I am thinking I have two separate problems. But could use diagnosis help before throwing parts at it.
History of Occurrence.
Three weeks ago truck was running great, CEL came on and P0136 showed up. I pulled the code, cleared it and it did not return for a couple weeks. The CEL did return but intermittently on and off the last week to ten days. Last week, with no visible CEL illuminated, the truck started missing badly under acceleration. When I drove it the next morning it was fine again. Still no CEL. The misfire returned again yesterday and persists today. About 1500RPM it gets really rough but smoothes out over 2K. Idle is a bit rough at 600 with a stutter in the needle when the rough idle happens. Seems a tad worse once engine reaches full operating temp. It is very cold here in Chicago lately if that matters.
Differential Diagnosis
Before reading the forums I thought the problem was a bad cat causing both issues. But that seemed odd at only 120K. After reading I find the P0136 code is Bank 1 Circuit 2, which is passenger side DOWNSTREAM? of the cat? There seems to be some confusion on the posts on this. Guys keep talking about replacing the UPSTREAM one with this code? Still others the downstream one. As I read it, its downstream. Anyway, if it is the downstream one I have read it has no function on engine performance even if the sensor is bad, it only reads info. So the misfire would not be related?
Plan
My thought is to replace the DOWNSTEAM O2 on the passenger side and check the wiring around it. Then swap the 1 and 3 COP’s to see if I have a bad COP which is the most likely cause of a misfire on 3. The plugs were changed at 105K at the dealer. The #3 or #4 COP was done at that time too, don’t recall unfortunately. But I should be able to see on COP #3 when I pull it. Isn’t #3 notorious for going bad due to water condensation?
Any thoughts or advice would be welcome. Could these issues be related? Or am I ok sticking with the current plan of attack? Thanks in advance for your time and knowledge.
Got a couple of problems with my 2000 2wd XLT 5.4L with 120,000 miles.
I pulled two codes tonight and researched them both. P0303 and P0136. After reading I am thinking I have two separate problems. But could use diagnosis help before throwing parts at it.
History of Occurrence.
Three weeks ago truck was running great, CEL came on and P0136 showed up. I pulled the code, cleared it and it did not return for a couple weeks. The CEL did return but intermittently on and off the last week to ten days. Last week, with no visible CEL illuminated, the truck started missing badly under acceleration. When I drove it the next morning it was fine again. Still no CEL. The misfire returned again yesterday and persists today. About 1500RPM it gets really rough but smoothes out over 2K. Idle is a bit rough at 600 with a stutter in the needle when the rough idle happens. Seems a tad worse once engine reaches full operating temp. It is very cold here in Chicago lately if that matters.
Differential Diagnosis
Before reading the forums I thought the problem was a bad cat causing both issues. But that seemed odd at only 120K. After reading I find the P0136 code is Bank 1 Circuit 2, which is passenger side DOWNSTREAM? of the cat? There seems to be some confusion on the posts on this. Guys keep talking about replacing the UPSTREAM one with this code? Still others the downstream one. As I read it, its downstream. Anyway, if it is the downstream one I have read it has no function on engine performance even if the sensor is bad, it only reads info. So the misfire would not be related?
Plan
My thought is to replace the DOWNSTEAM O2 on the passenger side and check the wiring around it. Then swap the 1 and 3 COP’s to see if I have a bad COP which is the most likely cause of a misfire on 3. The plugs were changed at 105K at the dealer. The #3 or #4 COP was done at that time too, don’t recall unfortunately. But I should be able to see on COP #3 when I pull it. Isn’t #3 notorious for going bad due to water condensation?
Any thoughts or advice would be welcome. Could these issues be related? Or am I ok sticking with the current plan of attack? Thanks in advance for your time and knowledge.
Cargo Master
Joined: Apr 2003
Posts: 3,476
Likes: 224
From: Frequently frozen MN
OK, your post is actually quite informative
I'm not an expert, but
1. When I looked up 0136, it was generic for bank 1 sensor 2 -- that's the rear O2 sensor, which is supposed to check for damage to the cat.
The explanation was that the O2 sensor showed a fault -- not the cat. So, it SHOULDN'T be related to your misfire. O2 sensors do fail.
Since that code should not relate to your engine operation, or even emissions ( as long as the cat is ok), you COULD spend time trying to troubleshoot it further. If you could get a hold of a good scanner, it will show what the sensor output is. It's supposed to be pretty steady -- and I THINK somewhere mid range.
2. Sounds like you have a plan to start figuring out the misfire. I've never owned a 'modern' Ford, but from reading these forums and other sources, COPs seem to be a little fragile.
One guy posted once that he saw where water could leak into the spark area from a coolant line. He rigged up something to prevent future problems. (sorry I don't have more details, but it was a while back).
My quite uninformed advice would be to focus on the misfire.
Good Luck,
hj
I'm not an expert, but
1. When I looked up 0136, it was generic for bank 1 sensor 2 -- that's the rear O2 sensor, which is supposed to check for damage to the cat.
The explanation was that the O2 sensor showed a fault -- not the cat. So, it SHOULDN'T be related to your misfire. O2 sensors do fail.
Since that code should not relate to your engine operation, or even emissions ( as long as the cat is ok), you COULD spend time trying to troubleshoot it further. If you could get a hold of a good scanner, it will show what the sensor output is. It's supposed to be pretty steady -- and I THINK somewhere mid range.
2. Sounds like you have a plan to start figuring out the misfire. I've never owned a 'modern' Ford, but from reading these forums and other sources, COPs seem to be a little fragile.
One guy posted once that he saw where water could leak into the spark area from a coolant line. He rigged up something to prevent future problems. (sorry I don't have more details, but it was a while back).
My quite uninformed advice would be to focus on the misfire.
Good Luck,
hj
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Cylinder 3 is in missfire. If you run with a missfire long enough, the cat health could be affected.
If it over heated, the harness could have been burned causing the 136 code.
Don't know what you have but those are possibilities.
Good luck.
If it over heated, the harness could have been burned causing the 136 code.
Don't know what you have but those are possibilities.
Good luck.
Elder User
Joined: Aug 2001
Posts: 942
Likes: 0
From: South Texas
A down stream cat O2 sensor code can be caused by many things, but the MOST likely cause is upstream of the cat.
Anything that throws the exhaust gas stream out of balance MAY affect the cat efficiency and set a code.
I would fix the misfire issue first. The misfire may be loading the exhaust stream up with unburned fuel that the cat cannot scrub out, setting the code for the O2 sensor. Once fixed, If the cat and O2 sensor are good, the code will most likely not return.
Anything that throws the exhaust gas stream out of balance MAY affect the cat efficiency and set a code.
I would fix the misfire issue first. The misfire may be loading the exhaust stream up with unburned fuel that the cat cannot scrub out, setting the code for the O2 sensor. Once fixed, If the cat and O2 sensor are good, the code will most likely not return.
Thread
Thread Starter
Forum
Replies
Last Post
jmlkicker
1987 - 1996 F150 & Larger F-Series Trucks
0
Aug 4, 2015 12:00 AM
JSTJ704
1987 - 1996 F150 & Larger F-Series Trucks
5
Jul 23, 2014 07:44 PM
