Idle - Low, But Steady

[happylexus450]

Good afternoon...first time poster.......97 lx 450, that suddenly seems to prefer idling steady at 400, versus the recommended 600-700? my experience with IACs is that it the rpm bounces all around, not remains low, but stable...

Any suggestions as to what the issue might be? Need to fix, or let it go???

Thanks

[indiasfinest]

its hard to understand what your saying..can u explain? is your rpm steady?

[happylexus450]

its hard to understand what your saying..can u explain? is your rpm steady?

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Yes, simply put, the car is idling at about 400, instead of the recommended range of 600-700....I have not noticed any fluctuations in RPM while stopped, idling and if I had to take a guess, it probably started this about a month ago. Prior to idling at or about 400, it was idling at the recommended range.

I hope this explanation helps.

[Rookie]

Well, I think this is one of those that falls into the category of "could be a lot of things". You should probably start with a good cleaning of the throttle body. Over time, alot of carbon and deposits build up on the throttle plate. If you've got an FSM, it walks you through the removal process. Remove, clean with carb cleaner, blow out the passages with compressed air and replace. I would also check your air intact tube that runs between the air filter and other vacuum lines that run off the TB, for cracks.

Good luck,

Rookie

[indiasfinest]

i understand but i dont no the awnser LOL....srry

[happylexus450]

Well, I think this is one of those that falls into the category of "could be a lot of things".  You should probably start with a good cleaning of the throttle body.  Over time, alot of carbon and deposits build up on the throttle plate.  If you've got an FSM, it walks you through the removal process.  Remove, clean with carb cleaner, blow out the passages with compressed air and replace.  I would also check your air intact tube that runs between the air filter and other vacuum lines that run off the TB, for cracks. 

Good luck,

Rookie

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Yeah, all of those items are fine.....I would think it might be the throttle position sensor or idle control valve, but the rpm's remain steady - almost as if it was set to that level...could the ignition timing be off a bit???? Would that cause a lower than normal idle rpm???

Thanks

Brian

[Rookie]

could the ignition timing be off a bit???? Would that cause a lower than normal idle rpm???

Thanks

Brian

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Wouldn't be my first guess but it's easy enough to check if you've got a timing light. Just warm up the motor and jump terminals TE1 and E1 on the DLC1 (located on the passenger side fire wall in the engine bay) with a paper clip. Factory setting is 3 degree BTDC.

The other suspect to check may be the MAF meter. Don't know if you have the FSM, but it has a inspection procedure and the appropriate resistance that should be measured across terminals THA and E2. Then also connecting a voltmeter + to terminal VG and - to terninal E3, then blowing air through the MAF and check that the voltage fluctuates.

Rookie