New Tesco Momentum 99 fuel

Putting higher octane fuel in (in itself) shouldn't cause any worse running. The only thing it might be, is a bad batch of fuel. I've known ill effects the other way round, though (ie putting lower octane fuel in causing poorer running).

different fuel can be funny, as My old cx500 bike ran lovely on asda juice, but not on tesco, especially the high octane stuff. it went like a scolded cat on shell optimax though. The golf hates asda fuel, pinks like hell on it, yet it loves optimax and tesco 99. dislikes total exelenium and bp ultimax though.

I think some of it comes down to what additives they use, as well as how long it's been sat in a tank being stored.

it could also be that your timing has been retarded, as that allows engines that should have 98ron run happily on 95. if you put 98 in it often hates it. I've seen this on a few mk2 16v's as the cheap fix when 4/5star went was just to retard the timing a few degrees to stop the pinking.  Makes them cheaper to run but trades in about 5-10hp and a bucket of torque.

Jon.

studs said

I took my GTi to Knebworth today & stopped at an Esso petrol station in Woolmer Green(Herts) & they had 4 star leaded petrol,
I thought I would treat the golf to some leaded fuel, couldn't see the price anywhere, so I picked up the pump,
then put it straight back down again:-



 £1.89 a litre :doh:

There's a firm that still sells it, as 5% (IIRC) of fuel sales can be leaded (not LRP) fuel. The distributor is - I think - called Bayford Thrust.

Digifant-equipped cars (as this is a Mk 1 form, that'll be the two 2H engined Cabbies then ) have a knock sensor and most definitely benefit from V-power or similar. Most other cars will have had their ignition timing retarded in the '90s as leaded fuel became unavailable generally; IIRC you'd generally knock it back 5° or so. There was something of a boom in those little mobile tuning vans around the time! One in Kelso made my Chevette run better than any Chevette I've driven since and it's a shame I can't find people that do that sort of thing as cheap these days; when the Golf gets a Weber fitted it'll need setting up…