thinkin this motor definitly needs a dealer diagnosis . but two things come to mind shees either not compressing the fuel sufficently on cold because of cylinder of other wear .or the pump or injector timing is off due to settings timing or coding and yes by taking the connectors off while the engine is runniing can upset the coding as they are coded into the ecu recognitioon and pump timing ..we once came across a broken wire to the cam sensor and needed new wiring or this .but expert diagnosis by reputable dealer seems only good path to follow in my opinion and then at least you knoow were your heading..e