Sounds a bit strange. Can't imagine running lean is causing your problems. I have 272 degree cams with standard ecu and grey injectors and it runs fine. Yes it could do better but I am getting around to that. The pink injectors (late 86kw FWD injectors) you have flow only fractionally more than the greys, so unless the greys are clogged up, not worth bothering about. I would seriously examine your cam timing and then get your static timing right.
Preume you are running a standard ECU? Have you bled the cooling system properly so there is no airlock at the back f the head? If not the idle will constantly go up & down. Etc, etc, etc.