Injector #7

Just had Injector #7 replaced on regen system on my 2008 Volvo D16. Immediately after getting truck back the throttle had a sluggish response. After shutting truck off for approx. 15 minutes and restarting, it was difficult to start, as though it was starving for fuel, then finally it started. Driving down the highway it seems like it's slowly running out of fuel, but when I take a ramp, it seems to clear. The idle is also surging. Mechanics are leaning towards injector cups, I'm not because this was not a gradual process and the truck was running perfectly, other than the regen, before having injector 7 replaced. What are the chances that the problem is a mistake made when they replaced injector 7, or it is injector cups???

 

Turns out it was the injector cups and one injector. They made the necessary repairs and the truck is back on the road.