Issue with start the engine in the warm/hot temperatures surging idle

[James.carne123]

Hello everyone, if you know issue with my 1990 Lexus ls400 have start in the cold morning is very normal for 1,100 to 1,200 rpm in the cold engine and wait for start engine get warm up about 5 to 10 mins. I was try test start in hot engine and that idle got out of control up and down and up for few seconds (1,200 to 1,400) then go back to 500 to 600 rpm is fine and quiet. I’m finish with cleaned out a ISV and adjusting a TPs so far. my old ISV from eBay is 23 ohmn and 24 ohmn between should be good to go. I will check out my currently on my ISV on my car for this week. If that is both are in good condition then check a leaking vacuum air use with cigarette smoke to see smoke out of the air. I don’t have put coolant in it. My car is running great start in the cold running and all day but only have issue with starting—hot engine (surging idle in warm coolant temperatures) probably need a coolant temperature sensor for sure. I’m still wait for coolant temperature sensor from Lexus website for almost one month from now.

 

[Zuffen]

Fix the known issues first then see how it runs.

You may be surprised what the coolant temp sensor does.

Very hard to fix any issue whilst the car has issues that should be sorted first.

 

[James.carne123]

Fix the known issues first then see how it runs.

You may be surprised what the coolant temp sensor does.

Very hard to fix any issue whilst the car has issues that should be sorted first.

Right now, I was get to super busy in last week. Finally my new temperatures sensor will arrive on Monday. I hope that would be issue away. I try to look up in that website and there is nothing about hot engine surging idle. I suspect that air vacuums leaking out of nowhere tiny holes cause my idle get low about 400 idle. Next week I will try do that with smoking cigarettes or vape smoke to find air suck in the engine. Also my engine get leaking. I suspect that value cover gets worn off and moon half in too .

 

[James.carne123]

Fix the known issues first then see how it runs.

You may be surprised what the coolant temp sensor does.

Very hard to fix any issue whilst the car has issues that should be sorted first.

Forget one of oil leaking, I can smell oil from vent air. I’m looking in this website mostly people said value cover is so sure and check out on half moon is very rare issue.

 

[James.carne123]

Update! My car is running much better after I replace a new temperature and found out back of engine near farewell camcraft rear leaking