How do you differentiate between the two engine harness plugs? I've searched and surprisingly found nothing considering this is such a common mistake.
I replaced my k20a2 engine harness and the car wouldn't start, unplugged both TPS and MAP and it barely ran, switched them and it starts but idles really high and keeps rising.

 

I can tell the difference by the lenght of the harness.Their is an arm in the harness with your Map plug , Air temp plug , and your gas vap purge plug all on the same arm. Then right were that arm comes out of the harness theres another plug, should be shorter. Thats your Tps plug. If that still doesn't help, check your grounds. Do you have Kpro?

 

It's not that easy. I thought I had it right because of the length of the harness but I just had it routed a different way. The best way to tell is that the TPS is the one whose middle wire is red.

 

I have already had the same problem. You can check the color code of the wires , length of the wires , or just know which ones they are from doing so much work on k series. I edited my first post to help you find it better.

 

I've made this mistake before it's easy and stupid... but I did it on my GSR... The sad thing is they keep making those two plugs next to each other identical... wtf

 

Label before disconnecting.

No problem later.