Hi guys,
I am going to try and make this easy to understand as possible so I am going to try and get straight to the point here. I’ve done some research but I can’t come across a legitimate answer.
I run a b20vtec all motor stock build with the itr intake manifold and an s2k throttle body. I am running into an idle issue. Now, when I start the car in the morning, it is supposed to idle in the 1500-1700 rpm range and gradually drop to 900 or so. But when I fire her up it immediately drops to 900 like it’s at normal “operating” rpms. I had recently changed out the tps sensor but I think I might need an s2k tps than a b series or are they all the same? I am positive I calibrate it correctly to .5V at idle and 4.5V at WOT. It is just the idle thing that doesn’t seem right to me. Could it be the throttle cable? Throttle plate? I am kind of lost.
There is a slight backfire also when I downshift coming to a stop. Would that possible be my timing or tps position? I apologize with this series of questions but I need some direction here. There’s no cel but it is definitely not running as smooth as it should be.

Thanks.