Is it a fuel, or fuel pump problem?

[MintyFresh]

Hi guys,

On the way to Rotorstock yesterday i topped up my half a tank of Optimax with some BP Ultimate.  From that point on the engine has been pulling back and hesitating.  Then on the way back i put anoothert 20 quids worth of Ultimate in, and i still had the problem.  
without the seats or buckets fitted in my car i could hear the fuel pump making what i thought was a \'different\' noise.  I say different because i dont remember hearing the pump untill yesterday.

So what you say there is a problem with the fuel mix, the pump, or something completely different?

cheers.

[Andyp]

I put £10 of ultimate in mine when I was desperate once and felt the car was acting up.. havn\'t used it since... i\'d run every last bit out (few top speed runs should do hehe) and then fill up with optimax again see if it still does it then you\'ll know

[MintyFresh]

Ok, cheers bud, i\'ll do that