I just bought this car at an auction, check out low it idles! It sat for about 8 months, and I filled it up with 93 and drive it about 10 miles and it still idles so low. It runs pretty smoothly, although I think it could be a bit down on power. Any suggestions?

 

My '99 sc400 idles the same. As far as I know it's normal. But I've been meaning to ask the forum about it..

 

Mine its the same

 

Yeah.. mine does the same but the only thing my coolant temp gauge hit the H and i goes into limp mode.

 

Hmm, thats too low of an idle imo. Should be at least around 600-800. Mine use to do that, i believe it was my O2 sensor.

scE4. if you let your temp gauge hit H you pretty much blew your headgasket i would assume

 

I check the temp of the engine with a scan tool and its reading 72 c. It doesn't over heat. Just that my temp gauge hit the H then when I start to accelerate it will drop down to normal. I've replaced coolant temp sensor.

 

After driving the car around for a bit it seems to idle OK now. I think it just sat for a long time, about 8 months or so. I just found out its the 300 though, someone put the 400 badge on the back!!

 

^ so you never opened the hood?

 

No, I rushed in towards the end of the sale and didnt think to

 

^ WOW..

Anyways, anyone have any real answers to the low idle problem? Sometimes I worry my car is gonna stall out on me while at a red light. Obviously it never does, lol. But I'm curious to hear from other 400 owners, and what their idle is at.

 

IACV probably. Same thing happens to mine everyday. Runs great for 15 minutes on my way to work, then I'll stop at a light and the RPM's will creep down to 500 or less sometimes shutting off. Turn your A/C or lights on, and it should raise back up. Either way clean your throttle body and IACV. Someone else mentioned it could be a vacuum leak.

 

Mine also does that but only in drive or reverse. On a cold start it'll idle at 1250, sometimes going up to 1500, and then drop down to 700-900 rpm (all that while in park).