Here's the story, I'll try to be thorough without being long winded.

Prepping a friend's 2003 LR Disco with 98k miles on it for sale. It's a pretty clean ride, but right now it's riding as rough with a lot of hesitation when you accelerate and some sputtering. I don't know the complete history of the vehicle, but I'll tell you what I do know.

- 20k miles ago had a head gasket job done at a local shop.
- shortly after that the front, driver's side O2 sensor was replaced.
- 30k miles ago (time of purchase) had the forum's 60k service performed.
- couldn't hear it in the truck, but had a little tick coming from the back of the passenger side of the head.
- SES light was on, and was also blinking.

Got it today, and here's what I went ahead and did.

-Oil was dirty, and added sea foam to the oil, then did a sea foam treatment through the vacuum system.
- Changed the oil, had previously been using Mobil 1 10w-30, but I switched it to the Rotella T 15w-40 that everyone on here has raved about. Didn't hear the tick anymore.
- Alternator was bad, so I changed that out.
- When you're driving it, it really acts like it's got a vacuum leak, but after spraying it with carb cleaner, I couldn't find a leak anywhere.
- Ran the codes and here's what I got.

P1300, P0308, P0307, P0301, P0132, P1129

I believe the SES light had been on for sometime, so tomorrow I'm going to clear the codes and run it again once the light comes on again.

My thought is that all O2 sensors should be replaced, What else am I'm missing with these codes?

 

Start by checking to make sure the front 02 sensor wires are not crossed that would correct the 1129, then replace the Bank 1 Sensor 1 02. Afterwords, plan on plugs and or plugs and wires to correct the misfires. What color are the plug wires and when were they last changed?

 

Mike,

Plugs are black and were changed at 70k by a LR dealership. I have a full set (front and back) of Atlantic British O2 sensors, in your opinion should I go ahead and change them all out? It's my belief that the rear sensors are the originals and nearly at 100k miles.

I know there are several opinions, but what would your suggestion be for plugs and wires? Thinking about it, it would have made sense to put new plugs in after the head gasket job (20k ago), but I'm not sure that was done.

 

If the dealer installed their wires, that is most likely the issue.
PM me your number and I'll walk you thru what to check.

 

Thanks for the parts recommendations today Mike. After I got off the phone with you I got the O2s switched. I don't know what code it was, but the front passenger O2 wasn't even plugged in...