Poor performance solved

Thought fellow K12 Micra owners might be interested in a problem which I had solved with my car. I was losing performance, especially at low engine speeds, which was most noticeable after reducing speed on motorways and A roads after sitting at constant speeds with very little actual movement of the accelerator pedal. I'd back off the throttle and when I went to accelerate again the car became very sluggish and would then only respond if full throttle was used. There was no engine management light on, the car is regularly serviced and everything is as it should be, plugs filters etc all in a very good condition. There was simply no reason for this problem and it went on for many thousands of miles, much to my annoyance. My local Nissan dealership hadn't got a clue what was causing it and stuck it on the computer countless times but to no avail. They tried to cure it by replacing an oxygen sensor in case it was starting to fail but not enough to put the management light on. I even bought a secondhand electronic accelerator pedal thinking that could be the problem but this did not solve the problem either.

After a recent 500 mile round trip when the car was "playing up" again I went to a local non-franchise garage and explained the problem. During the conversation I had with the owner he asked what position the temperature gauge was at when running with a warm engine but, of course, K12's don't have one! He suggested that the symptoms sounded like I could have a faulty thermostat causing my engine to run too cool, as opposed to too hot when the coolant warning light would have illuminated. He said this fault would be most obvious under the conditions that I was experiencing the problem.I took his advice and replaced the thermostat and amazingly the problem has been fixed!!!!

The most annoying aspect of the whole saga is if the car had a temperature gauge I woud have noticed the vehicle was running too cool and would have been able to have had the fault recified long ago. I hope my experience might be of assistance to fellow owners who might be experiencing a similar problem.