Hey All, lately I have been experiencing issues of hard starting my 98 lexus gs400 and was wondering if someone can help shine a light on the issue, I've searched this thread high and low and tried some troubleshooting to no avail.

Anyways here the issue is my car intermittently starts w/o issue. But most of the time the car cranks and begins to start then stalls out, but if I don't press the accelerator down then the car will start.

Also, worth noting is in park if I give it some gas to 2.5K rpm, and let off the accelerator the rpm drops a little below 500 rpm for a couple of seconds, almost to the point where the car will stall out, but eventually recovers and crawls back up to the idle rpm of ~725 rpm.

I don't think it is a fuel issue being that I check the fuel pressure to the fuel rail and it was in spec ~45- 50 psi.

Also checked the resistance of the Throttle Position Sensor, Throttle Position Motor and Throttle Position Motor Clutch, all were in spec'd in respect for resistance.

Any leads of what to check or adjust next?

 

https://www.clublexus.com/forums/gs-...rol-valve.html

Salim