I’m having trouble with the motor at idle it wants to surge at idle and drops cylinders. Once you bring the the throttle up off idle it starts to run fine at quarter throttle all the way to wide open. There are no codes or lights on. The computer has been gone through and that did not change anything. The fuel injectors have been gone through. Compression is good on all four cylinders. New fuel filter and the fuel pressure is 28 psi.