CarCrazyLS400 Posted November 26, 2008 Share Posted November 26, 2008 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. Quote Link to comment Share on other sites More sharing options...
vroom8 Posted November 28, 2008 Share Posted November 28, 2008 mine does that too, very unstable startup. i have just noticed it this winter. once it is warm, it is fine. Quote Link to comment Share on other sites More sharing options...
eatingupblacktop Posted November 28, 2008 Share Posted November 28, 2008 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. Quote Link to comment Share on other sites More sharing options...
landar Posted November 28, 2008 Share Posted November 28, 2008 Just curious, Vroom and CarCrazy. What type of fuel do you typically run in your LS...regular, mid-grade, or premium? Quote Link to comment Share on other sites More sharing options...
vroom8 Posted November 29, 2008 Share Posted November 29, 2008 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 Quote Link to comment Share on other sites More sharing options...
silvermistLS Posted December 3, 2008 Share Posted December 3, 2008 TPS (throttle positioning sensor) is most likely bad. Hook it up to diagnostic. Quote Link to comment Share on other sites More sharing options...
don corleone Posted December 7, 2008 Share Posted December 7, 2008 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. Quote Link to comment Share on other sites More sharing options...
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