hi all im off the topic of fords but a mate has just rebuilt an engine for a toyota celica 2l 16v and we fitted it 3 weeks ago, since we fitted it the engine has had a miss fire, flat spots and generally poor performance, it popping and spluttering back into the airbox. we have changed the plugs leads ect. could this be a timing problem or somthing. ps the old engine run fine oil rings had gone thats why we changed it. any help would be appreatiated thanks juffer