P0301- Cylinder 1 misfire. Restricted Performance. Rough idle under Load. 2012 LR4

[Red Top Engine]

Trying to get to the bottom of this gremlin:
On cold startup, the engine will idle rather rough. Under load, it will hesitate a climb. Check engine light will flash, go into restricted performance mode. On restart, it will operate but still somewhat sluggish. Engine performs better after it was warmed up. With the exception of the injectors and throttle body control unit, all actuators and sensors (including both MAF, all O2 sensors, Plugs, Coils, cam sensors, coolant temp) were replaced during an engine rebuild I did within the last 2 years. Reading codes off GAP tool, no tell tale signs of anomaly aside from Cylinder 1 misfire. I'm wondering if there are specific components that are more prone to premature failure that can contribute to this?

 

[Rover Range]

I would say the #1 injector is restricted.
I would try the BG44K, as directed by BG.

 

[Red Top Engine]

Will swap the coil pack- test- replace all plugs & test and finally replace the injector. Keep you posted!

 

[jlglr4]

Injector seems likely to me as well, could be clogged but might also be failing open and flooding - much more likely to cause the restricted performance I think.

 

[Red Top Engine]

Found the problem: Bad Coil. The cylinder 1 plug did have a little oil on it but it didn't make a difference in engine performance after putting new one in. The moment I replaced the coil pack (on cyl 1), stumbling & hesitation stopped. Swapped around with a spare twice to confirm. These coils I purchased from AB less than a year ago so rather surprised they failed so early. They don't have the same FoMoCo insignia as OEM. Leaning on replacing all with OEM, as who knows which of the other 7 will fail shortly.

 

[M32H32IS]

Are they Bosch or Delphi?