Got stopped by local Police in Northern NJ because the silver Jaguar plate cover was covering up the bottom of the NJ rear plate. Only $54.00 dollars later did I even realize there was nothing to do. Believe the officer was looking to issue ticket to obtain his quota, as he claimed and I counter claimed a speeding issue. Be careful if you put the Jaguar cover over any plate in any state that it does not cause a problem.

Second topic-Have had my XJ8 on the rode since 1/07 and on my own discovered that Sunoco 93/94 ran it best.Engine was replaced at a cost of $17M to Jaguar in 09(thank God for warrenties and some integrity by the dealer). At the same time spoke with my tech guy about the proper gas to use and he showed me forms/policies from Jaguar UK/USA that they recommended that exact brand and octane. Fast forward to last year when had 35M miles on the new engine and started to get "knocking" at low speeds. Told this to dealer who "worked" on the "sulfer" mix in an attempt to fix the knocking-which failed. Two weeks ago, by circumstance had to use a tank of Shell 93 which of course eliminated to this day all the knocking and gave the car a real feel of POWER!

Is the above change in brand to the "V-Power" of Shell just a "lucky" way for me to solve a problem or is there any negatives with this brand of gas or is it just a change in the seasonal formulas of the brand. Any help is very much appreciated. Thanks and All the Best Bernie

 

I'll leave the fuel issue to the experts to comment on.

I take your point on the license plate holder, I believe it would be illegal in AZ also
the word Arizona must be visible at the top of the plate and the forum plate would obscure it.

 

I believe the plate issue is a problem in many, if not all US states, including clear plastic plate covers. I know NC, where I currently reside, they have started cracking down on that law over the last couple years. I still have not taken off my plate frame which happens to cover the state name. Generally local law enforcement around where I reside could care less about stuff like this, unless you give them a reason to pull you over for something else and are being a jerk, and thus they start looking for what else to get you for.

On your brand of fuel point, I believe sulfur was eliminated from North American gas almost 10 years ago. I don't know how much a difference it makes to my X350 that I've had for going on 10 years, but I know brand of fuel has made a huge difference to my previous cars. I had one car that ran substantially better with top grade Sunoco and my prior car ran substantially better with top grade Shell. I use top grade Shell in the Jag 99% of the time, and haven't noticed any discernible difference when I've occasionally had to fill up with something else. I never fill up at no name places. I notice fuel efficiency taking a hit with some tanks of gas, presumably based on the amount of ethanol content. That said, if your car is running better on a brand of gas, then stick with it.

 

Bernie, part of it may be the ethanol content in the gas. Some gas stations refuse to sell part ethanol gas and therefore have a loyal following from those that feel the price difference is offset by the better mileage that they get (straight gas is more expensive per gallon than the ethanol blend).

The other thing to consider is that even though both gas pumps that you use quote 93 octane, all that is telling you is that the minimum octane rating is 93. In reality, some gas stations request that their 93 octane gas actually be say 95 octane. The trick here is when the state comes in to sample their gas to verify that they are selling a good product, if they are found to have gas that is even 0.1 octane less than they are advertising, it results in them having big fines. So, to prevent that, they request that the fuel be made with a higher octane than they advertise. Now the question is, how much above does the station request. Some will go say 0.5 octane higher, others will go 3-4 octane higher. So, the "same gas" can be dramatically different.

Also keep in mind that each station requests a unique mix and quantity of detergents be added to the gas. There may be one of the detergents that your car doesn't like that the Shell station just happens to not add to their fuel.

As you can see, there are lots of possibilities as to what is causing what you are seeing. So, without doing a lot of analysis of the gas and whatnot, if you know what works in your car, stick with it.

As for the license plate bit, having lived in more states than I care to admit to, each state has their version of what is acceptable on the license plate. Like Idaho, you have to keep the bottom of the plate visable so they can determine what county you live in. Other states say you can't have anything covering any part of the plate (clear or not), regardless of how small it is. This is where knowing your local laws can really **** off a cop when they give you grief over a suspected problem and you pull out the state law and show them how they are wrong. I had to do this a few times with my truck as they said I was too tall and I ended up printing out the law, a few pictures of my truck with a tape measure next to it, and then telling them that they are more than willing to remeasure the truck. Normally they stomped off in a huff and told me to watch how I drive.

 

Hi Thermo, forgive me if I have misunderstood...are you saying that each individual gas station in the United States of America specifies and orders a custom mix of fuel? Surely not, I can see that a particular corporate chain of stations might do that; if correct that must affect the production costs and retail prices ...or have I misunderstood? Many thanks Allan

 

Allan, each station is able to specify their own mix. But, as you pointed out, the cost can get high. So, as a general rule, a given brand will have a mix that they use and the station owner gets a cut in the price if they use it. But, the mix for Shell is not the same as the mix for BP, which is not the mix for Wawa, which is not the mix for ...... Hence why you will find that using a different brand of gas will sometimes cause your car to run better/worse. That is also why I tell people to periodically switch to a different brand because the detergents in the gas are slightly different and they will affect how the gum and tarnish left behind by gasoline is removed and by switching to a different brand, you raise the likelihood of keeping everything clear. If all detergent blends these days did a 100% job in removing stuff, then why do we still end up with clogged injectors and the like? I will admit that things are better these days than they used to be. But, they are still not perfect.

Does this clear things up some? I guess my use of "each station" may have been too broad of a stroke, should have been more "each company".

 

Thanks everyone to responding to my two topics...yesterday put 350 miles on the car and used a half a tank of Sonoco and a half of a tank of Shell and got 30.0 miles per on 95% highway driving.....will live between brands and see what happens.....thanks again for the responses. Bernie from Tenafly NJ.

 

Thanks Chris, much appreciated - putting me straight on this. Thanks Allan

 

The same recommendation was made by the head chemist from one of the big refiners. In his case, you know that this cost personal money because fuel of his own brand went on the company credit card while fuel of another brand came out of his pocket. His particular recommendation was to switch every six months or so.

On the difference between brands in the case of the OP, it may boil down to something as simple as the way the tanks and filters are maintained at a particular station. Many people who stick to a brand also tend to stick to a specific station because it is the most convenient location.

 

PLums, I think if you ran a tank or two of a different brand every 3-6 months, then most people should be good. If after 2 tanks the problem is not removed, then you are looking at other issues and you need to take the actions to the next step.

 

I'm only recounting the story as a third party confirmation of the concept from someone who is quite credible. In his case he was happy to switch back and forth on the calendar, so that's what I reported.

Although I am not a switcher, for me it takes a month or more to run through a tank. So, if I were to do this, a six month schedule would make sense.

I notice a big difference with non-ethanol Shell V-Power(better idle, logged LTFT) as compared to the other major refiner brands, so I'll stick with it unless it seems necessary to clean out some accumulated deposits with another brand.

 

Another V-Power fan here!