Ford Fiesta

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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.