I thought I knew my engine bay like the back of my hand, and was blaming my idle surging and stalling problem on the H/C/I I had put in. For about 2 weeks I was doing the idle reset and having good results initially but only to have the problem pop back up. Idle would surge and die, hang high 1100-1200, and surge stall when comming to a stop. I tried every approach setting the idle at 1000 and even 700 with poor results, tried setting TPS at all different settings too. Finally I spent some SERIOUS time just following vac lines and learning where they when and why, and that's when I found my problems...wish I could narrow it down to one thing but I found a few. First I discovered the orange hego ground was not connected (now it is), next I found my PCV grommet was not really snug so pulled it and inserted the PCV into it the grommet and wrapped the outer dia of the grommet with electrical tape to get a nice tight fit into the lower manifold. Next and my favorite..I after going over the vac lines 5x I found a broken line just inside my passenger fender well and replaced it 
. The result is....850-900 idle with no surging and computer is compensating nicely on the RPM's as they drop with NO SURGING and NO STALLING, the idle is lopey as it should be with the XE270hr-12 but is reliable and comes to a stop with good RPM manners. This is a long story but I hope someone out there with a simular problem can find some useful info to help them out. I have spent probably 20-30 hours under that hood over the last 6months swapping the engine, painting the bay, trying to tune, and I NEVER saw the problems. Spend the time going over these simple basics and you may end up saving some serious coin by not trying to throw money at the problem..could be a piece of tape and vac hose is all you need. Again sorry for taking up so much space. Oh and by the way I took my baby out tonight again and with the new set up finally runnig properly I let her have it to about 5000 in 3rd..um all I can say is my car was SLOW with the old motor, now it feels like it weights half as much as it did cause the RPM's just hammer up the tach and you can FEEL it put you in the set like never before..I look foward to some full throttle blasts to 6000 in a few hundred miles BIG TIME.
. The result is....850-900 idle with no surging and computer is compensating nicely on the RPM's as they drop with NO SURGING and NO STALLING, the idle is lopey as it should be with the XE270hr-12 but is reliable and comes to a stop with good RPM manners. This is a long story but I hope someone out there with a simular problem can find some useful info to help them out. I have spent probably 20-30 hours under that hood over the last 6months swapping the engine, painting the bay, trying to tune, and I NEVER saw the problems. Spend the time going over these simple basics and you may end up saving some serious coin by not trying to throw money at the problem..could be a piece of tape and vac hose is all you need. Again sorry for taking up so much space. Oh and by the way I took my baby out tonight again and with the new set up finally runnig properly I let her have it to about 5000 in 3rd..um all I can say is my car was SLOW with the old motor, now it feels like it weights half as much as it did cause the RPM's just hammer up the tach and you can FEEL it put you in the set like never before..I look foward to some full throttle blasts to 6000 in a few hundred miles BIG TIME.
