How to use PICO with OLED and MOSFET?

I am working with a OLED over I2C and use module "SSD1306".
Some times I only see lots of dots instead my text, guess I have to add pullups (4.7K) to SDA and SCL.

this is what's working for me:

// running on esp8266, 1v85.MaBe_master_6c6dc46

I2C1.setup({sda:D4,scl:D5});

function go() {
 g.drawString("Hello World!",2,2);
 g.flip(); 
}

var g = require("SSD1306_I2C").connect(I2C1,go,{height : 64,contrast : 127});

// switch disp off
I2C1.writeTo(0x3c,[0,0xAE);

// switch  disp on
I2C1.writeTo(0x3c,[0,0xAF]);