My mate has an escort Rs Turbo and it has all the power there but is holding back it boosts fine and the timing has been checked does anybody know what it might be this is what we have tried, dizzy cap, rotor arm, inlet manifold gaskets all 3, rocker cover gasket, fuel pump relay, fuel ecu, air filter, ignition leads, we have taken all the hoses off and checked that they have no splits in them. we have got to the point where we dont know what else to change