Had my car serviced a few weeks ago. Same day after service i drove my car on a dual carriage way for a couple miles. After coming off dual carriage way i got stuck in traffic and my car started to make like a blowing noise as if the engine was over heating. First time for my car to do this and ive owned the car for 3yrs. Then yesterday after coming off a dual carriage way i could smell a burning smell from the engine. Then today when i was back on the dual carriage way and hitting about 70mph my steering felt light. And same again car smelt like it was burning. Checked under bonet no smoke or couldnt see any leaking. But there is a dark black ring around end of exhaust. No burning smell if i avoid dual carriage way and stick to 30mph.
Many cars don't get the right sort of use for passive regeneration to work so car manufacturers build in ‘active’ regeneration where the engine control software senses that the filter’s getting blocked and injects extra fuel into the engine to raise the exhaust temperature and trigger regeneration.
Active regeneration will be initiated every 300 miles or so depending on how you use your car and will take 5 to 10 minutes to complete. But it’s a problem if your journey’s too short and the regeneration doesn’t finish.
During active regeneration you may notice:
Cooling fans running
Faster engine idle speed
Automatic Stop/Start doesn’t work
Increased fuel consumption
A hot, acrid smell from the exhaust.
The engine sounds different
You didn't say what engine in original post . From the further info it could be your clutch slipping or the engine cooling fan not coming on . If clutch slipping , engine revs up with a power loss . Check coolant level also .