Namestaletoolong

Hey everyone. As the title says, my rx300 idles at 980-1050 in P and N after its up to temp. When it's shifted into drive, Idle drops to 730-750...

On cold start it immediately hits 1750, drops to 1500 within seconds and continues to drop over 2-3 minutes until its at 1000....

If I shift into gear before the idle comes down, it obviously jerks the suv....

I see posts everywhere saying 600 is normal idle....

I replaced the TPM (yes correctly, not manually adjustable )
ABSOLUTE TP is at 13.33 when it's warm. Had to reset battery after install, (was up to 2000 on cold starts before the relearn)

I also replaced the IACV. And Cleaned the throttle body completely and for fun replaced the MAF sensor.

Then i checked for vacuum leaks, none of the hoses are damaged and they are all going to their homes.

Any input? What is normal idle for you guys? My 2014 Honda warms up at 1200 and settle in at about 800...

salimshah

750 rpm at idle after warm up is good.

You mentioned the IACV was replaced. Was it by any chance an after market product or purchased from unreliable source.

Can you please expand on the name TPM.
Have you had the idle issue for long? Was it ever normal? Was something done to the vehicle that triggered the issue?

Also can you ensure that there is at least 1/8" slack in the throttle cable at the air intake.

Salim

Namestaletoolong

Hey there. To clarify, it is idling at 1,000 rpm when warm. It doesn't drop to 750 until I shift into Reverse or Drive....

Sorry, it was a typo. TPS Throttle Position Sensor.

They are non-oem. But have great reviews from verified buyers.

There were no codes at all before i replaced them and cleaned the throttle body, but the car was idleing at about 900 in drive and about 1,300 in park before i swapped them out.

Seems ALOT better now, but like I said, everyone else is saying it should idle at 600rpm.

Thanks for your help!

salimshah

First gen RX is still the old way of cable controlling the throttle. The TPS has the word throttle, but that is used for kick down the gear box to lower gear [instead of the old carbureted engines which had a squirt fuel reservoir]. TPS change or malfunction does not impact idle. Newer vehicles do not use the cable and the portion of the throttle is used by ecu to understand the driver's intention. In skid condition the throttle can be backed off by the ecu, but for first gen the throttle is hard wired.

My questions about IACV, vehicle history have been not answered. If some tampering has been done, that needs to be undone or corrected.

Please confirm that there is slack in the throttle cable. Well adjusted cable needs to have 1/8" to 1/4" slack.

CEL has lot more to do with emission standards and very little with idle speed. The vehicle idle is controlled by IACV which is governed by ecu.

Salim

Australian

Under load you have less revs would expect it to be normal. My first thought is air filter and some new flow will make a difference if you feel it is sluggish. Even if filter looks clean it may be blocking air. I know how fast things clog even if look clean. You can make a pond with geofabric and sediment same materials. There are some poor filters on the market and could show a near new one that blocks flow.