P0139 code and cheap gas -- related?

[Finn Dunn]

Hi, I bought my first LR just before the end of last year. It's a 2004
Disco II, currently at 37,000 miles.

Being ignorant and cheap, I thought I'd save some money, so I've been
running it on 87 and 89 octane for the past 5k miles.

Now I've got SES light on and P0139 code.

Does anyone think the cheap gas could be the cause? Can I clear this up by using something like BG 44k or should I just resign myself to changing out the O2 sensor?

And lastly, what is the effect of driving with this code on? Is it only an emissions issue, or can it lead to other problems?

[jmrivera]

Looks like the savings you've incurred with the cheaper gas can go towards paying for repairs now....

Has your engine been knocking since you made the change?

You may have to Seafoam your truck and change the 02 sensor... Plugs may have to be changed also - you could pull them to check for carbon...

[Finn Dunn]

Yep... learned my lesson the hard way.

Actually the engine runs fine, which lulled me into a false sense of security.

When you say Seafoam it, do you mean seafoam in the gas or something else. I've seen reference to a few different ways of using seafoam.

Thanks.

[Elemental]

NO NO NO!!!! Your fuel quality had nothing,zip,zero to do with this. You have a slow O2, it happens, the part failed, no biggie.

Your fuel ecomomy will suffer SLIGHTLY from this. The O2 sensor isn't sensing fast enough to keep your fuel at Stoichiometric. No biggie really.

Your emissions will increase, but slightly.


You didnt learn a lesson, there is no lesson to learn. The part is just bad.

[Finn Dunn]

ok, cool... thanks...

Either way think I'm staying switched to premium... consensus seems to be that it's money well spent.

Thanks again.

[Disco Mike]

By switishing back to high octane you will regain some power and about 2MPG.
Go to Atlantic British or Rover for good prices on the correct 02 senor for your truck.
Might want to find a can of B&G's 44K to clean up your engine.
Mike