hello am new to the site and was wondering for some advice.
i have a mk5 escort with a escort turbo engine fitted had it set up on the rollers and it hit 184bhp at 16psi. that was with a slight miss so i changed my plugs leads and all that , now the miss seems to have gone , but they advised me to use a high octane fuel . so the otherday i put some optimax in and now its seems to run worse .. now it might not be anything to do with the fuel . what its doing it once it has warmed up to normal temp when i floor it it will come up to boost and hit about 5000rpm and it will sorter stop reving higher drop down a bit then pick up and go and sometimes get the odd backfire.
any one had problems like this ?
the car is chipped so i cant see it being a limiter or anything . its just weird how its occured now i put optimax in

i have also noticed it is reving higher on idle i have adjusted the idle screw its in as far as it goes . is idling now about 900rpm

thanks for any help