Solved the issue disconnected negative. Car runs smooth when I do this. However as soon as I plug negative on battery terminals it runs like crap. What can this be?

Spent 1000s trying to repair this and today I discover when I simply disconnect it runs fine.

Thought it was injectors, ecu, fuel pump, cam sensor and crank sensor replaced all of this.

 

Wait so what exactly is your problem? Do NOT run the car with the negative terminal disconnected, it puts huge amounts of loads on the battery. All the negative terminal is is a ground. Find where it's grounded and clean it up? Are you saying you 2nd and 3rd cylinder are not firing correctly?

 

I don't get the post really.

What have you tried? Also how is compression and leakdown then.
We should start with good mechanical before we jump to other stuff.

 

Cylinders 2 and 3 don't fire when you have the negative cable to the battery connected??

 

Yep fixed it bad ecu