Curtisgnar

Car runs great no stutter or vibrations but when at a stop light in gear it drops all the way down to around 2-400 rpm.

Recently repaired my ecu with new japanese caps which fixed major problems so that is out of the question .

Gonna start by checking throttle body and TPS , maybe IACV?

Heard this is a common issue, can anybody give me some ideas . Thanks.

400fanboy

Those are good places to start, IACV in particular. Not just checking, but cleaning. Is the transmission fluid healthy? Air filter healthy?

Tallyhoe

I'm having a similar issue, will follow this thread as I may have a similar outcome. My issue is just when ECT Power is turned on I get the low idle and stalling. When it's off idle is normal and no stalling. 93 SC400.

Curtisgnar

My LS developed an erratic low idle that quickly became stalling a few months back. After that it started dumping raw fuel into the motor and causing a number of problems. It ended up being a bad capacitor in the ECU. It runs great now other than a slightly low idle when the AC is off . It’s always a safe bet to check the ecu before replacing 20 parts like I did. Those SC’s are a sweet *** car I’m jealous.

Tallyhoe

Thanks, I've had the ECU rebuilt already, maybe I'll have to send it back for a recheck... I had eratic idles, low idles and stalling until I got it repaired, but the issue continued a week later until I replaced some relays and works just fine until now.... Makes me consider an expensive standalone ECU probably would be a similar price as a rebuilt one off lf Lexus or Tanin minus capacitor issue of course.. but a whole new can of worms there...