BP diesel cures flat spot?

[Daveandsharan]

About March time I started to experience a flat spot between 2500 and 3000 revs. The car refused to accelerate even with my foot to the floor.

Then one day, the emissions warning light flashed and the engine management light stayed on.

Having read various threads on this forum, I was contemplating whether to pay my local independent for a diagnostic, or whether to just poke and hope and change the MAF and the MAP and hope this would solve the problem.

Over the next few weeks I drove the car as usual, no long trips, but always reaching working temperature and with the warning lights still glowing.

Now I usually use supermarket diesel, but one day I had to use a BP garage and filled up with their basic diesel, not premium.

After a couple more short journeys,  typically 15 or 20 mile round trips, the engine management light went out and the flat spot disappeared!

Three weeks later, everything is great! The car accelerates in all gears and is running really well, so I have continued to use BP diesel.

I wondered if anyone else has noticed a difference in performance when using branded fuel?

[Daveandsharan]

This was my VW Sharan AUY engine.

[johnnyroper]

I have never had this issue with diesel as I donââ,¬â,,¢t tend to use supermarket fuel,mainly because in a previous petrol car it ran like a dog on Tesco stuff. Always used branded stations after that. So entirely feasible supermarket diesel could have a similar affect

[SirDavidAlhambra]

I always use the best shell diesel I can find. The car seems to run really well on it

[brianh]

I have never had this issue with diesel as I donââ,¬â,,¢t tend to use supermarket fuel,mainly because in a previous petrol car it ran like a dog on Tesco stuff. Always used branded stations after that. So entirely feasible supermarket diesel could have a similar affect

Funny you single out Tesco petrol there, as thats the only one I've found the same problem with, and the longer I tried to use Tesco petrol in it, the worse it would run. Was absolutly fine on Shell or Asda though!

[johnnyroper]

Very odd I am not the only one I just assumed it was my car not liking it,I did use Sainsburyââ,¬â,,¢s on the odd occasion where I left tank run a bit low but didnââ,¬â,,¢t have the same issue. Must be additive pack related as the fuel originates from the same refinery. Even the 99 octane stuff (whatever they call it these days) provided similar results.

[SirDavidAlhambra]

I image Tesco just sell the cheapest stuff they can get their hands on, bp and shell are more premium brands so probably have better additives in the fuel

[brianh]

Very odd I am not the only one I just assumed it was my car not liking it,I did use Sainsburyââ,¬â,,¢s on the odd occasion where I left tank run a bit low but didnââ,¬â,,¢t have the same issue. Must be additive pack related as the fuel originates from the same refinery. Even the 99 octane stuff (whatever they call it these days) provided similar results.

Same here - used Sainsburys no issue at all. Only reason I don't routinely use theirs is that there isn't a local station of theirs here, so its only if I'm passing one. Don't think its necesserally a cost thing but certainly something that certain cars just do not work well with for whatever reason. Not that I use so much petrol now as I used to. Not tried the 99 octane stuff, as there seems little point unless you have a vehicle that actually needs it or benefits from it.

[mike wilson]

Stopped using "cheap" fuel for precisely this reason well over a decade ago.  Closer to two, now I think of it.  Used to use Shell after that, as there was a station on my way to work.  I once filled up by accident with the premium stuff and found an immediate improvement in MPG, although that might have been right foot paralysis due to financial shock.  When travelling abroad, I use exclusively premium diesel from one of the big makes or the national equivalent.  I usually only need to fill the tank two or three times, so it's not too much of a wallet killer.

Nowadays, I use exclusively Costco diesel as they brand it as a premium product and that seems to be the case.  Good MPG, no misbehaviour and it's about 2-3p cheaper than standard big brand prices and much cheaper than their premium brands.  Before leaving work, I was doing enough mileage that the savings on fuel covered the membership cost.  That has more than halved, so the situation needs to be reassessed.

P.S I don't think BP does a premium diesel.  Never seen it round here, for sure.

[johnnyroper]

BP have ultimate in petrol and diesel I donââ,¬â,,¢t really use it much as only really see BP stations when going to Birmingham when in the car,not many BP stations round my way.

[Mirez]

Funny you single out Tesco petrol there, as thats the only one I've found the same problem with, and the longer I tried to use Tesco petrol in it, the worse it would run. Was absolutly fine on Shell or Asda though!

Tesco fuel routinely puts my "Water in Fuel" warning light on in the Transit. You don't really notice a problem as such but it can't be good!!

[SirDavidAlhambra]

I would be horrified if I had a water in diesel light light up on my Alhamb!!!

Yes, you just canââ,¬â,,¢t beat quality fuel from shell or bp etc

[mike wilson]

BP have ultimate in petrol and diesel I donââ,¬â,,¢t really use it much as only really see BP stations when going to Birmingham when in the car,not many BP stations round my way.

Maybe I'm thinking of Esso.  One of the big makes used to do a premium petrol called something like Trillium but there was no equivalent diesel.