One of three things could be restricted; fuel(plugged filter or weak pump),
air(filter or debris in inlet), exhaust(cat converter damaged or
muffler/tailpipe collapsed). Without any diagnostic data to look at, I can
only suggest to start with the basics that any engine needs.
>I have a Fiesta '93(K) 1.1 CFI (push rod) engine with 85k on the clock It
> will start and tick over fine but develops no power so top speed is 45-50.
> I have changed plugs/leads/head gasket had the clutch checked for slipping
> and put additive in the fuel - no joy. Does anyone have any (polite,
> practical) suggestions on what to try now?