I have a 02 LR Discover 2. I am throwing a P1300 code with multiple misfires. I am also throwing a P0152 (O2 sensor) code. I have changed all of the spark plugs and all of the O2 sensors. Can the o2 sensor be causing the misfires? Is there any way to test or take the O2 sensor out of the equation? Can anybody offer some help?

 

P1300 is derived from variations in the crankshaft speed fluctuating. A single misfire is defined as more than 1.875% per 1000 revolution. Multiple misfire Catalyst Damage is defined as more than 7.4 to 14.6 percent per thousand. This will turn on the CEL either in two drive cycles, or right away, depending on some other parameters.

Basically, your engine is running rough, and if you keep driving it will be expensive to fix.

The code P0152 is:

O2 sensor circuit high voltage (bank 2, sensor 1) Front sensor RH bank short circuit to battery supply

This indicates a crushed cable or messed up connector or connector contaminated with something. The voltage to the sensor is wrong.

Since the O2 sensors are part of the decision of what mixture, they might have something to do with this, but the norm for misfires is spark plugs, spark plug wires, and coils. Coils are the last to change out, because you have to take the intake off to get at them.

 

Thanks a lot for the response. I have a new set of wires coming in next week. I'm heading home tonight to make sure the gap on the spark plugs is correct. I think that may have something to do with it too.

As far as the O2 sensor goes, I'm going to trace the wire and see if I can find any faults in it. if its the connector, would you happen to know where to get a new conector? I'm assuming they woult sell portions of the wiring harness>

Thanks again

 

Whos plugs did you install and at what gap? Who's wires are you planning on installing?
Check the 02 connection for oil or grease, if dirty clean with contact cleaner and reconnect.

 

Check the passengers side front O2 connector for green corrosion. Back when I was a greeny about Rovers the dealer kept my car for over a month trying to dianose a bad idle and it ended up being a corroded O2 connector. Its an easy fix but often overlooked. Your new spark plug wires may also solve your problem.

 

I just swapped out the plugs with Bosch Platinum +4 and tightened them down with torque wrench at 18ibs. I also put half a can of seafoam into the engine. she seems to be running a lot better. i still think the wires need to be changed out, when i get on the gas it still stutters a little bit. Ive ordered a set of standard wires. some of the wires connecting to the plugs seem a little loose to me. I'm getting a few new codes too. I cleaned the connection on the O2 sensor with sensor cleaner. the P1300 code seems to be gone for the time being but now im getting misfires in 3 4 and 8. they are not as sever as before the plug switch. the new codes are P0154, P155, and P300. Anybody have any ideas? Thanks again for all the help!

Side note: this beast has 93k miles on it, it doesn't look like the spark plug wires have ever been changed.

 

Help, I just replaced all of the spark plug wires (Standard 7mm) on my LR Discovery 2 and I am still getting multiple misfires. I have also replaced the connector on the wiring harness for the O2 sensor and am still getting a no activity code from that sensor. How can I test the wiring going to the O2 sensor to make sure they are functioning properly? I looked at all of the wires all the way up to the harness on top of the engine and everything seemed fine other than a random wire in the harness that didn't go to anything. I have 4 wires going into the connector that connects to the O2 sensor. after replacing the spark plug wires she did seem to run a lot better but I am still getting Misfires. Does this sound like the coils are going bad or is this 02 sensor causing all the problems? I'm trying to figure out if I need to order new coils since i would have to overnight them in order to get them to me before the Thanksgiving weekend. Any help would be greatly appreciated! Dan