glenmore Posted September 11, 2008 Share Posted September 11, 2008 I have a 1990 LS400, about 150m. In hindsight, the RPMs at idle slowly began to drift lower and lower down to about 400. I did not pay much attention as the car ran perfectly smooth. It was about due for some maintenance so I did a bunch of stuff together, caps, rotors, plugs and wires. I had to replace a bimetal sensor because it just disintergrated when pulling off the vaccumn lines. Upon restarting, the car idled roughly and then died. After checking my work, the car died a few more times and then ran fine but still had a very low idle RPM of about 400. Shop found nothing and just cleaned the throttle body. The car went on a 400 mile road trip and has been driven occasionally during the week since late July. The car runs fine with the low idle RPMs and my daughter has only reported early on two isolated incidents of stalling. I am beginning to suspect a plugged up or failing IACV. Anyone have success at cleaning one of these things? New ones run $600! glenmore 1990 LS400 1991 300CE 2000 C280 Quote Link to comment Share on other sites More sharing options...
IS400 Posted September 12, 2008 Share Posted September 12, 2008 I have a 1990 LS400, about 150m. In hindsight, the RPMs at idle slowly began to drift lower and lower down to about 400. I did not pay much attention as the car ran perfectly smooth. It was about due for some maintenance so I did a bunch of stuff together, caps, rotors, plugs and wires. I had to replace a bimetal sensor because it just disintergrated when pulling off the vaccumn lines. Upon restarting, the car idled roughly and then died. After checking my work, the car died a few more times and then ran fine but still had a very low idle RPM of about 400. Shop found nothing and just cleaned the throttle body. The car went on a 400 mile road trip and has been driven occasionally during the week since late July. The car runs fine with the low idle RPMs and my daughter has only reported early on two isolated incidents of stalling. I am beginning to suspect a plugged up or failing IACV. Anyone have success at cleaning one of these things? New ones run $600!glenmore 1990 LS400 1991 300CE 2000 C280 I'd check the trunk ground wire (Black) that runs along the drivers side hinge. My car runs amazing after I resoldered that wire. It is a common problem as you will find if you search for 'trunk wire' or something similar on this board. ;) Quote Link to comment Share on other sites More sharing options...
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