After installing my new motor, my idling in my car became very hesitant ( at around 1500 RPM it will oscillate back and forth unless i give it more gas) I have a new Skunk 2 intake manifold, but still using the b17 throttle body wit all the sensors orignially from the b17 motor (TPS, MAP) I have a modified ecu for my b18c so i dont think its that problem, but when i put in the motor i used original harness ( i heard i can get an obd1-obd2 adapter, or vise versa cause i dont knwo which OBD i am ) . Please help! What are the first things i need to check ( like the basics).

thanks everyone
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Moe