Cold Morning Start Ups

[CarCrazyLS400]

Hey everyone,

Just recently, my LS400 has developed a bouncy-type idle when starting it in cold weather (between 10-20 degrees F). It tends to go from 800-1200 RPMs sporadically.

Any ideas on what could be the problem? From winters past, during cold weather start ups, the RPMs would be steady at about 1200 until it warmed up.

Any input is appreciated. Thanks.

[vroom8]

mine does that too, very unstable startup. i have just noticed it this winter. once it is warm, it is fine.

[eatingupblacktop]

Just recently, my LS400 has developed a bouncy-type idle when starting it in cold weather (between 10-20 degrees F). It tends to go from 800-1200 RPMs sporadically.

Sounds like your IACV needs cleaning.

mine does that too, very unstable startup. i have just noticed it this winter. once it is warm, it is fine.

Could be yoiur cold start injector.

[landar]

Just curious, Vroom and CarCrazy. What type of fuel do you typically run in your LS...regular, mid-grade, or premium?

[vroom8]

i use high grade fuel 91. i've only noticed it since the weather has gotten colder, once the engine is warm, it is fine.

thanks blacktop

[silvermistLS]

TPS (throttle positioning sensor) is most likely bad. Hook it up to diagnostic.

[don corleone]

might wanna clean your throttle body. mine had as much guck as the one in the tutorial. here it is.

http://www.lexls.com/tutorials/EFI/throttlebody.html

might just take it off and see if it is dirty. make sure you buy a new gasket too.