i just bought a 1990 civic hatchback si for $400, the person i bought it from thought it had a cracked head to i had it pressure tested and it was fine so they shaved it and it was the the head gasket, i got the car running but on theres something wrong with the fuel injection system. when the car is running i take off the number 2 and 3 fuel injector plug ins and the idle doesnt change but if i unplug the number 1 and 4 the car almost dies, ive replace the injectors but that wasnt it. plz write me some suggestions of what i could be

 

Maybe you don't have spark in those 2 cylinders?