OK so Iv'e had this problem and have been searching all over the net for the last three days for an answer to no avail.

here's what I have
sbc
comp cam off road cam
zz4 intake
stock tbi
18 psi fuel pump

Iv'e been working on this retro fit for the last two months and have never had much of an idle problem, at least not after i got all my blm's in line after a few weeks of timing. I finally got everything running great. blm, pe, spark.....everything was great! I could hit the gas and go with no problems. I finally decided to take it out for a long drive. before that it was all just around my neighborhood. well after about 20 min of driving it started to stumble and stall while idling. I finally got it home by two footing at every stop light. I have since changed the rotor, spark plugs, tps, and iac. I have also done a iac re learn about ten times. still nothing. I watched the temp sensor with tuner pro and it stayed right in line with my mechanical autometer temp gauge. the only thing I havent changeD or checked voltage on is my map but have looked at it with tuner pro and it doesnt really look like the readings are off but I def need to do a little more in depth looking at it. Here is the strange thing.......while idling at around 700rmp its really rough and eventually will die but when I disconnect the cts it will smooth out and idle great, a little high around 600-650rpm but none the less it runs smooth and wont stall. I plug it back in and it will stumble and die.
also there is no emissions stuff at all on the engine.

I'm at a loss. does anybody have any ideas for me?

Ihanks

 

Do a cts test, measure the ohms while you heat up the sensor in a pan of water.

 

Well I finally figured it out last night and to be completly honest i feel like a retard lol. after going over everything with the DVM and checking for air leaks I figured it must be a mechanical problem with the engine. Well for whatever reason a lightbulb went off in my head telling me to check the voltage to the ECM. 9.5volts! Ah ha! I traced it to a loose connection and started it up. Fixed! so after everything I went through it turned out to be something that took me two seconds to fix. Oh well, you live and learn. Now every time there is a strange problem like that the first thing I'm going to check is the voltage to the ECM lol.

 

This sounds like my idle problem to a T! When it's a rough idle warmed up if I disconnect the CTS it will idle but not perfect but low but it don't stall... If I connect it bam it dies... I'm going to trace my ECM after work today... I hope this fixes the issue!