RB20 problems and slow to lose revs? (Video inside)

[S14Ryan]

Hey guys,

I have an RB20 swapped S13 that i've been trying to diagnose a problem on and I am stumped at this point and need some assistance. It seems that my car is very slow to lose revs once it hits about 2500 RPM on the KA tach(so the RPMs are inaccurate but just for the sake of explaining) and I did a boost/vacuum leak test and everything was fine and holding pressure. I had originally thought it was a vacuum leak causing it to let in air past the TB. I have a feeling it may be the IACV but i'm not sure how I would go about testing it, I tried unplugging it and it didn't seem to do anything or run better. The car also runs fairly rich and has a misfire at idle when it starts to warm up, however the cold idle doesn't miss as much. I have a feeling that may just be ignition coils. I also noticed the oxygen sensor is not plugged in and I could not seem to find the pigtail on the harness for it, but i'm not sure if that would be a problem?

Any insight would be greatly appreciated!

Video of revs hanging:

https://www.youtube.com/watch?v=bNLQ_HdSvM4

(Embedding isn't working for me, sorry)

[Yellow4g63]

Sounds like maybe a bad coil or spark plugs. Did you set the ignition timing right?

[S14Ryan]

Sounds like maybe a bad coil or spark plugs. Did you set the ignition timing right?

Plugs are brand new NGK BCPR6ES gapped correctly, i'm fairly sure the coils are junk but it drives fine, no misses on throttle. I haven't touched the timing but would timing really cause revs to hang like that?

[Yellow4g63]

Cant really say for sure since the tach is getting the wrong signal.

[Syrus33]

clean the iacv at the back of the intake. double check all coilpacks. make sure it is running on all 6 cylinders. also the 02 sensor will cause it to run rich, Also might want to make sure the tps is set correctly.