I suggest you check the throttle body for carbon deposits and the
idle control system .
IDLE SPEED CONTROL (ISC) Actuator the idle speed control actuator is the double coil type and has two coils. The two coils are driven by separate driver stages in the ECM. Depending on the pulse duty factor, the equilibrium of the magnetic forces of the two coils will result in different angles of the motor. In parallel to the throttle valve, a bypass hose line is arranged, where the idle speed actuator is inserted in.
The IAC may just need cleaning , when this malfunctions it will set a code but if no codes then just may need cleaning ,
Check for vacuum leaks bad vacuum hose connections or miss routed ,
Hope you did not use Bosch spark plugs as theses will give you problems .
No code idle problem is normally a dirty throttle body ,IAC dirty ,miss routed vacuum hose or damaged ,vacuum leaks .
Need further assistance with this issue please get back to me.