Using lower octane gas is *not* going to cause effects after you switch back to other fuel. Also 87 octane fuel doesn't contain any more particulates, contaminants or other things that would cause a fuel filter to clog any differently than 93 octane. Think about it.

But -- if you're taking 11 seconds to get to 60 on a p400 defender, you have a serious problem that's not related to fuel octane - sadly I think your best course of action is drop it off at the dealer with a very specific written recap of what you have experience.

 

I just clicked on the link provided and read the accompanying article. I’m sorry, but either that article was transposed from a third world country, or was written by a 6th grader, but it definitely did not seem like a technical publication. The grammar, and sentence structure had me scratching my head to understand. There were contradictions to other statements the article posited, and sentences that made no sense. I’ll keep looking for another source of information. But in my experience, these vehicles need the octane they were designed for; in a pinch it’s okay to use lower octane until the next fill up, but not for the long term.

 

Thanks, good to know.

It is so weird, I left my house this morning, the truck was a beast. Parked at work for a couple of hours, left to a jobsite, and it's like I'm missing 2 cylinders...
I tried disconnecting the negative terminal of the battery but it did not make a difference.

Is there a way to reset the truck back to factory settings?

 

A quick update, I'm dropping it off at the dealership to replace the charging pad and check acceleration issue.
Yesterday, I have noticed that when it is cold outside (California cold - 58) it drives better vs during the day when it is hotter. I tested the acceleration twice during the day and once again at night, the difference is substantial.
I don't know if that has anything to do with it, it is definitely not scientific but the daytime video shows 11 seconds acceleration (in the video it is from second #7 to 18). Same day, later that night, after the truck has been resting for about 3 hours. The evening video shows ~7 seconds acceleration (from second #22-29)
I stitched both vids together so the difference is clearer.

 

Interestingly in the second video the transmission is shifting early, at like 5500 each time. In the first one it’s shifting nearer to redline.

 

It almost feels like it is gasping for air when it revs up like that... So i looked at the muffler, and it looks odd. I saw two other defender on the road today, non of them had ANY heat marks on the metal. What is even worse, is that it is more so on one side. Could it be a clogged/defective muffler?

The left side shows it is heating more so than the right side. The other Defenders I spotted on the road today did not have discoloration on the muffler at all.

 

Maybe a tank of bad gas damaged a catalytic converter. That would restrict performance and be worse as the temp of the vehicle increases.

 

The other Defenders probably didn’t use 87 octane fuel. Maybe that’s why they did not have discoloration on their mufflers. Best practice to follow the manufacturer’s recommendation.

 

A quick update;
I picked up the Defender from the dealer on Friday, they claimed to have found the issue. It was a recall of a rigid diaphragm of a PCV valve... I'm not sold. It is definitely better than before, but still not 100%.

In the paperwork they also did not address the discoloring/heating difference between the two sides of the muffler. I tested the two sides of the muffler and the right side (not discolored) is exhausting noticeably better.
Could that be the issue?
I'm bringing it back to the dealer next week for a charging pad replacement, I'll bring it up to my advisor.

If anyone has a similar experience, please let me know. I noticed another Defender in the shop with a similar discoloring, but dozens of other ones with no discoloring at all. I'm thinking that there could be a recall for the muffler...

 

Thanks for the feedback Paul.
Would you please explain to me why it would get worse as the temperature increases?
I'm taking it back to the dealer tomorrow and would like to give them all the tools to resolve this issue.
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