Recently failed mot on emissions x308 Daimler V8. Plugs changed,MAF sensor changed. On start up terrible misfiring wont idle etc. Pull off MAF sensor plug wait about 30 seconds put plug back on,perfect,idles,runs pulls like a train . Switch off when cold does same again. Scratchy head time.

 

The cold/bad - hot/good scenario suggests it could be a faulty temperature sensor. However, I'd get a scan tool on it to get a better idea of exactly what is happening.

Graham

 

Are you saying your unplugging the MAF while its running?

 

As suggested, better get a good OBD scanner and see if you can get any codes. The plug, or rather the contacts on these plugs, any plugs, tend to get corroded over time. And cause problem, unplugging and plugging them back on, might have dislodged some of the corrosion, but do a proper visual check as well.

Good luck

Jeroen