Hi

Just had a service on my 500 and driving home I removed eco mode and put my foot down a bit, only for it to lose all power. The injection light and general warning light came on and also start stop was now unavailable. Struggling home and pulled up, turned the engine off and then off again and the engine was fine and injection light gone. Took it for another drive and all was fine until I took eco mode off again. The same didn't happen again but the power seemed to dip around 3500/4500 revs. put eco mode on again and all was fine, no warnings at all now and start stop working.

Taking it back tomorrow but any suggestions or ideas? Oil, filter, and plugs were all changed

Thanks in advance

Had similar on both my 500s in the past month. Probably most relevant and posted on here last Sunday was my Twinair. Out of the blue on hard acceleration around 3500-4000rpm developed a misfire and the check engine lights etc. No issues in eco mode also.
Was a failing coil pack on cylinder no 1
1.2 500c developed a misfire/check engine lights and dropped into limp mode the day after its service with the specialist. Turned out to be a crap batch of Bosch spark plugs, as the replacements did it also, some 1300miles later... NGKs fitted and no issues so far.
So logically.. unless you are unlucky and you have a failing coil pack... its more likely something that has been done on the service... ie the spark plugs!

Sounds like the plugs is the most likely cause. When I bought plugs for my TA the only ones I found were NGK.