LS idle and coolant hose question
 

My 91 Teg jumps at idle when it gets warm. The cold idle is about 2k, which is fine by me. When it warms up it tends to jump when I'm not on the throttle. I've checked every vac line and have replaced them all. I'm assuming IACV? Anything else you guys could think of? Also, the vacuum diagram under the hood is all cut up, so does anybody have a picture or diagram for those vac lines. I just want to tripple check everything is in the right place

Now for question #2

There's a coolant line under the thermostat that was cut. I can't find where it could possibly go so I capped it. Does anybody know where this coolant line goes to? Thanks


Colin

Re: LS idle and coolant hose question
 

That coolant hose probably goes to the FITV (fast idle thermo valve) that is under the throttle body. The FITV increases the idle speed when the coolant temp is low, but at normal warmed up temps it closes to lower the idle speed to sub 1K. If no coolant flows to it, it can't function properly, thus your jumpy idle when the engine is warmed up.