Anyone have trouble running super unleaded?

Put £20 worth of tesco 99 in the other night, and since then the car has had a misfire low down (1000-2000rpm) and only under load.

Get it past 2000 and it takes off like a rocket like it always did.  It sits on idle fine as well, and revs freely with no misfire when there is no load.

Just wondering if the higher octane could be causing this  :dontknow:  Its a 16v KR, but dont know what the timing was set to as it was done on a RR last time and not by me, and loathe to start mucking up settings just to get £20 worth of juice to run right!

Has anybody had similar issues running super unleaded?

Cheers

Ross

Your supposed to run high octane fuel in a KR.  KR's have no knock sensor so cannot run standard fuel.  Somthings not right there, I suspect a dodgy batch of fuel (ive had this in my old KR)  once this is used up go and put £20 V power in there and note the difference.

KR's run like dog s**t on standard ron

I did wonder about a dodgy batch, a poor mix or something, as it has run super before no problem.  Its the only thing I can think of that would account for the sudden poor running, just a couple of miles after filling up.

Yea I imagine its a dodgy batch, i had it from a service station on the M4.  I think you can tell more in an older car as they are alot less refined in the first place.  Do yourself a favor tho and run super all the time.  Mk2 16V engines were not designed to run standard RON

lol, will do when I can claim my mileage back!

TESCO AGAIN . burn that 20 quids worth and fill up at a propper FUEL station not a filling station . some big stores use to many adatives cos if its watered down they dont pay tax on water . remember CORNWALL ibet the cornish can remind us . :? any takers

I have started running my 8v carb on shell super!! and it runs great! put standard tesco stuff in and its got a hell of a flat spot!!  

Funny the tesco round us used to use Texaco juice If I remember rightly, but all the cars that religiously used it went through silencers like no ones business and put out a LOT of condensation until hot, ever since they started using their own stuff there hasn't been anywhere near the problems like there used to. I tried a few tanks of Tesco fuel and always got 30mpg, Shell gave me 35+ mpg, that was the decider for me! Not tried the 99 super they do yet, but might have a play and advance my timing a bit :-) although VPOWER/optimax whatever they are calling it has always been the fuel of choice!

supermarket fuel is complete gash!! not worth the hassle for saving a couple of pence a litre, stick to shell garage's and you wont go wrong, i had a 1380 mini couple of years ago and it wouldnt get out of bed with tesco rubbish in and i thought i had serious probs somewhere! tried everythin coil plugs compression test etc then finally decided to drain the tank blow it through and put a gallon of optimax in, results were staggering!! pulled like a train no missfires!! lesson learned

Modern day fuel only last a few months before it goes off and some people say tesco buys fuel thats just about off and thats why its cheeper? I service and repair lawnmowers and we are always removing tesco fuel from them, they just wont run right on it at all, bad fuel effects a single cylinder engine more! Tesco fuel is very poor I always use Esso for my self and at work and we never have any problems!

interesting reading here

Slowstarter said

Funny the tesco round us used to use Texaco juice If I remember rightly, but all the cars that religiously used it went through silencers like no ones business and put out a LOT of condensation until hot, ever since they started using their own stuff there hasn't been anywhere near the problems like there used to. I tried a few tanks of Tesco fuel and always got 30mpg, Shell gave me 35+ mpg, that was the decider for me! Not tried the 99 super they do yet, but might have a play and advance my timing a bit :-) although VPOWER/optimax whatever they are calling it has always been the fuel of choice!

Funny you should say that - has been putting more steam than normal out when its warming up!  That is when it warms up - had a meeting this morning and it didnt want to play ball - so had to take the espace  

When I got back though managed after some cranking and nearly starting to get him going.  Left him running for a few hours to burn off more of that rubbish - nearly at the redline now so will fill up at esso tommorow and hopefully it will dilute it enough to get it running right again

rossirvine . can ya post on this thread your findings after a few days of running on good fuel will be interesting

my closeat station is sainsburys and it no where nere the quality of shell fuel tested the two in my mk2 golf when i had it, shell lasted longer and the car ran better used sainsburys and car used to cut out when i was coming to a stop

im very sure most or all supermarket filling stations are selling this type off fuel . cos i have tried the lot with all my company cars . if it was good stuf i would save a mint per year and think off the club card points .

Its probably got water in it, they all have it in, and I would imagine it plays havoc in this weather anyway.

I've used ASDA and Texaco lately, the Texaco seems to be better (MPG and running wise), can't comment on the rest.

i always use standard shell unleaded in my clipper and it runs well but im gonna splash out and put some optimax/vpower or what ever its called these days in it just to see if i can notice any running/performance improvements! i could tell with my mini so we'll see! i'll let everyone know!

well ran it down to start of redline, and then brimmed it with esso petrol.  Seems to be running better, misfire isnt as pronounced or lasts for as long, but its still there-assuming it will be as the rubbish is still there, just a bit diluted, so will see how it goes over the next few tanks

Was it the super unleaded you used? I always use it and never have any problems! You should be fine with some good esso fuel!

Seriously lads you cannot beat Shell V power... as soon as I fill up on it and drive away I notice a complete transformation