Chosen Solution
My husband just did a oil change, and oil treatment on my mama’s 2005 Kia Optima, and now when we start the car it idles very roughly, and when we put it in gear it almost dies. What could be causing this?
Okay, so you changed the spark plugs, check the face of the plugs and see what they look like. They should not be black with soot. Also change the wires since it is possible that they are cracked. If no result from that, it is possible that the Camshaft position sensor is not working right, as well as the Crankshaft position sensor. Clean the Idle air control valve, or replace it if necessary. The only other thing I can think of right now would be to clean the Mass air flow meter and definitely check the coils.
Same problem with our 2005 optima.. changed input/output sensors, both coil packs, both coil boots, spark plugs & wires, throddle position sensor. Still running like crap
Check your fuel filter
I had the same problem. Check the input and output tranismission speed sensor.
