Before I did the auto to manul swap, I remember there was a wire hanging under the car, close to the tranny on driverside. It was a two prong harness. I thought it was for the reverse lights switch, but when I did the t5 swap for the reverse lights to work I actually connected the two wires from old auto shifter and plug them into the switch on T5. Now I am wondering what the other wire was.

(T5 is WC with mechanical speedo)

The reason I am saying this is because I am having this check engine light after the swap. It has something to do with rpm I beleive. Like when I slow down in highways to exit or sometimes when the car idles.

The car also has higher rpm after the swap, but a little tap on gas pedal brings it down rightaway.

Would a manual ecm swap help? Does ecm on manul cars get any speed info from the tranny?

L03 89

 

What kind of car?

What color are the wires?

 

The car is 89 Camaro L03. I have to check under the car for the colors but seems like those are for electronic speedo.
The issue is the high rpm at the moment. I am looking for a manual ecm for that year...
By the way, how hard is it to swap a auto ecm to manual? it's just plug and play?

 

The check engine light was code 23 and 24.

I fixed 23, the air temp sensor was disconnected from under the air cleaner. So far no more check engine light.

I have this high idle tho, to bring it down I just need to tap on gas pedal. I am thinking of installing a spring on the throttle.

 

The computer is still looking for the 700r4 when you slow down. Adjustments needed to be made to the ECU so it can stop looking for it.