I've read a good "DIY" and know what to do. but im having trouble picking up a reading on the wires. Almost as if there not "live" but I had a garage set it before. So im pretty sure there's a signal but they left my idle at 1.4K so im correcting it now. Do you stick the lead(red one)in the plug(hole of the yellow wire) ? or just touch it to the wire after setting the multimeter to the right setting.

S2:70mm TB W/original TPS.
94 GS-R

 

need some input pls

 

Head is coming off soon. should i get it done now or after(Springs+retainers install) if i got it done now would i have to get it done again afterwards.