16 Vector XTX Cold Idle Speed Hunting

[jjreds]

I've had this sled for a few years and it has always had a temperature related idle problem. When cold it will cycle from fast idle to a low idle about every 5 seconds. High-low-high-low etc. until it warms up. When the sled is warmed up it idles perfectly. However when cold when it drops the rpm's from fast idle down to a low idle sometimes it stumbles and stalls. Some signal that is controlling the idle speed is screwed up? I'm hoping a guru sees this and has seen this problem before, thanks

 

[theCATman]

What is/are you calling a low idle? 1550-ish is what they are supposed to idle at.

How many miles are on it?

Has it always done this, or something new?

 

[74Nitro]

Leakdown or compression test the engine.

 

[Stubbs]

Could be a tight exhaust valve lash situation like many of the 1049 SR Vipers suffered from.

 

[CaptCaper]

My 16 xtx vector always had a non smooth idle when cold right from the startup everytime. But when warmed up it runs like a beast. 4500 miles now on it. My wife has a 13 vector ltx and had a 2010 ltx which had a flawless cold idles. odd.

 

[jjreds]

What is/are you calling a low idle? 1550-ish is what they are supposed to idle at.

How many miles are on it?

Has it always done this, or something new?

The idle speed changes fast for about 3 secs then slow for about 3 seconds alternating fast slow fast slow until it warms up. It doesn't maintain fast idle when cold. It's got low miles around 5K. I got it used. Always done it.