I have an 2014 Mazda cx5 2.2 diesel. The car starts without any problems when cold, and engine runs great without vibrations. Problems start after doing about 30miles on motorway when I come up to traffic lights or junction and have to stop. At this point engine starts to misfire and vibrate with smoke and smell of unburned fuel coming from exhaust. The start/stop system also works only on cold or not fully hot engine. The EGR and DPF have been removed by previous owner which eliminates problem with this system. I had injectors replaced with recon ones properly coded to the car.
I have 130k miles on the clock and accept that it is an old car but I think if there was a problem with compression on worn out engine, the car would not start on the first turn when cold.
No fault codes come up.
Has anyone experienced similar problems and found solution?
I would really appreciate your help

Zbig

 

Welcome to the forum

 

1st step, in-depth diagnostic scan.

2nd, monitor PIDS cold & hot( live data )

3rd Compression test
4th Leak down test.

5th Injector leak-off / flow return test.