Hi Roy
thank you for your help, this week I got holidays and repaired and mot'd the car,
you were rigth, I bougth a new replacement Lambda sensor , I attached a earth wire with a clamp to the body of the new sensor to assure a good electric ground and car changed totally, the mid range RPM is now perfect, with no weavy up and down rpm, just constant rpm
I added a new set of spark plugs for better burning of the fuel and WOW, exhaust gases gone, passed MOT perfectly.
now all is OK, both problem repaired thanks to Roy and all the other members for his help in this trouble.
best wishes
Jose
