I was wondering if someone can give me some general causes of a searching idle problem.
It 's fine when I start it and it's cool out, but after I been driving in traffic for a while or it's real hot out, when ever I come to a stop the idle jumps between 800-1800. The funny thing is the speedometer jumps with the rpms. When the rpms jump to 1800 the speedo reads 30mph and when it goes back to idle it goes to 0 mph.
I swapped in a T56 and I'm using a Dakota box to change the VSS signal from digital to analog. The Dakota box is mounted inside the center console near my shifter. It gets very hot in there.
Not sure if this is normal, the whole center console is warm to the touch. Anyway, I think the Dakota box is cooking which is making it give a funny signal to the ecm. The ecm trims fuel based on speedo input right? So if the ecm is getting a roaming signal from the dakota box that would explain my idle problems right?
Thx for your help btw.

Ben

 

I think you are on the right track. Can you disconect the speedo converter? If your surging goes away, you know thats it. Vss is an input to the computer, but it's not a major for fuel trim. Still electronics don't like extreme heat, so if you can relocate the speedo conveter to a cooler area.