Ford Escort 1.8 SI Lack of power

My 1998 Escort 1.8 SI is nice to drive and handles well however; it does not have the expected power or acceleration. New air filter and high quality
oil made no difference. I don't expect a racing car but when 1.25 Fiestas out accelerates you, there must be something out of tune. At idle the engine 'hunts', I have a Gunsens Gas Tester to check the CO but do not know the recommended reading or where to adjust the mixture. It may be more than the mixture, or maybe the car is just designed to be slow, does something need cleaning or replaced? Before I book the car in for an expensive tune up, has anybody got any suggestions that may make this car more responsive!
Many thanks in anticipation
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The engines may be too differnet but I have a 1.9 that was having the same problem and changed the plugs out with some OEM platinum plugs, gapped at .054 from Motorcraft and it runs much better. I changed them because it was lacking in power and the MPG was low. I have yet checked the mileage becuase I haven't driven it much this week.

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.