I helped my kid buy his first car and when we got home I realized it had a bad radiator leak. I pulled the radiator, and flushed the system. In the process of flushing the system, it began to run really rough.

I pulled the scan tool out and had a misfire on Cylinder 3. I found a variety of plugs on the car, but cylinder 3 had an RSX plug. Basically, it had 2 normal Denso, a different wrong RSX plug and another aftermarket one. I proceeded to check the coils and found the gap of the spark plug to be over .051. I fixed it but the car continued running rough. I decided to replace all the coils and plugs.

The idle seemed to be high, so I inspected and cleaned the throttle body. I disconnected battery and did an idle relearn. The factory intake hose was torn, so I replaced that before doing the idle re learn.

After doing the idle reset, the idle is now around 500 without a load. With a load it drops lower and wants to almost stall out. It feels like it is misfiring but there aren't any codes. I don't see any vacuum leaks.

Any ideas?