its a do it yourself diagnostics test. He may have the equptment to do it properly. If not its worth getting it done. I found somewhere to test mine (cost me £30) and it sent me straight to the source of the problem :)

Was the coolent temp sensor in my case, but it obviously isnt in yours as you have had that changed :boggle:

What's that then (I am not remotely car techy ) but I can at least tell the mechanic

have you tried the paper clip test?

engine management light comes on only when it's misfiring badly. When it's running ok it's fine.

engine management light on?
chow can you have changed carb and injector? do you mean tb?

I recently bought a 1.2 Corsa City which developed a problem on start up, the engine chugs and mis-fires badly & when driving loses power (I assume because it is only firing on 2/3 cylinders). My mechanic has changed the following distributor rotor / coil pack / ignitor / injector / plugs & plug wires / engine temp guage / carburettor. And yet every time I start it first thing in the morning when it is cold it continues to misfire and smells like it is dumping fuel into the engine. When I drive it later in the day when it's hotter (I live in Barbados so we're talking 30c plus) it runs fine. It's got me and the mechanic stumped.....any help most welcome.