sc400MOB

So.......my three issues im dealin with is......when I come to a stop from like 45 mph my car cuts off.when I pull off from park and stop it doesn't happen though.2nd is when I start my car it revs from 1000 to 1500...calms in a few seconds.sometimes it doesn't so I rev THE motor then it calms.3rd issue is is that my car will sputter 2 or 3 times when I pull off sometimes.but accelerates fine afterwards.the way I go around my car cuttin not cutting off is I throw it in neutral right before I stop.completely stop then shift to drive.slowing down for corners it wont cut off only when I make a complete stop.I was told it could be a maf sensor.I swapped it wit a good condition one.didnt help.returned it.was told it could be a janky throttle body.swapped a good one in.didnt help.check engine light isnt on!!! Car runs excellent besides my lil issues.PLEASE HELPPPP ! Lol.thanks and God bless.

bigwes

This is exactly what I'm going thru except I have an idle issue and when I slow down my car starts to sputter and act like its about to stall out but it doesn't. I have a really low idle when the car is in drive

SCereal

iTrader: (4)

Idle air valve? Was that swapped when you changed throttle bodies?

sc400MOB

I swapped only the throttle body and every thing thats supposed to be on it.where is idle air valve located?new sc400 owner.used to be a s13 coupe guy.just learning now about my lex.

SCereal

iTrader: (4)

Not certain on the sc400 I have a 300. I'd expect it to be on the throttle body however. Just some of the behavior sounded like typical iac issues. Lots of knowledge here so I'm sure someone will chime in.

Biddles

iTrader: (2)

What's your mileage? I'd take a look at the ECU for any signs of it being on it's way out.

SC400slide

iTrader: (11)

Sounds like the ECU. How many miles? Could also be coils and/or fuel pump ECU. If the engine has higher miles, it could be a solenoid that needs replacing.

Ramblerman

Could be a bad throttle position sensor also.

LS430forMe

Sounds like the Idle Air Control Valve. See if you can swap a used one in to see if it makes a difference.

LEXXIUM

iTrader: (1)

I don't think any one solved this yet, it happened to few people on the board, check all your ground connections, thuroughly inspect plastic intake pipe for cracks as well as tighten clamps.
There are many factors can contribute to that: lots of old sensors including foulty afm and ecu as well.
If this is a constant issue, you need to invest in a lexus sc300/400 fsm, a good multimeter and a little bit of a common sence.
This still remains a mystery....