How do I remove the plastic engine cover on my 2009 Kia Borrego 3.8L

You can't, test and replace it. It talks to the ECM/TCM

https://www.google.com/search?q=remove+the+inhibitor+switch+from+the+transmission+of+my+2009+kia+borrego

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you can get guide from many sites.. i know few
error codes/ fault codes, wiring diagrams, schematic diagrams, torque specs, engine info, switches functioning, assemble, disassembly, complete refurbish, repair, installation every single thing is covered
within seconds u can get the access and it's totally illustrative complete

The 2009 Borrego has a yellow engine icon that appears as a check engine warning on the left side of your instrument display.

What does this box do?

I have an '09 Borrego, the oil filter is located on the front of the motor below the harmonic balancer,
To access it remove the lower valenca panel under the front behind the bumper. There are 7 bolts holding the panel on, remove all 7 bolts and the panel will drop free. You will see the oil filter housing just above the sway bar and below the harmonic balancer. You can use a 1-1/16" socket and a 6"-12" extension to remove the filter cap. Make sure to get the V-8 filter, it is not the same as the 6 cyl filter.

The filter is located right in the middle, almost up against the firewall, after you pop the plastic engine cover. You must twist off a plastic cap and then pull the filter (a cartridge type) straight up and out. There are two replacement rubber rings that should come with your replacement filter. One goes on the plastic cap (just above the screw threads) and the other much smaller one goes at the end of a plastic rod that is connected to the cap.

Which engine?

3.8 top rear of engine, remove engine cover to gain access

4.6 bottom front of engine above sway bar and below harmonic balancer, remove the lower valance to gain access

Just grab it and pull straight up, it is mounted on studs with rubber bushings holding it in place.

My wife and I bought a 2009 Borrego with the 3.8 lt. engine. On start up the engine knocks for about 3 sec's. This happens cold,more so, and warm. Anyone have the same problem??? Service Manager says it's ok. Thought?

nazof is exactly right. Totally disregard emissionwiz and clint_carter. I have the exact same vehicle and have changed the oil and filter myself. The filter is located right in the middle, almost up against the firewall, after you pop the plastic engine cover. You must twist off a plastic cap and then pull the filter (a cartridge type) straight up and out. There are two replacement rubber rings that should come with your replacement filter. One goes on the plastic cap (just above the screw threads) and the other much smaller one goes at the end of a plastic rod that is connected to the cap.