Hey guys, My Sc400 does this thing where it will drop from about 1,000 RPM (where it usually is) to around 200 then no idle. If I take my foot off the gas it will just die so I have to drive with one foot on the gas and one on the break. It doesnt do this often but it just randomly does it and will just randomly start idling again. Any Ideas what the problem could be?

 

have you checked for codes? looks like you have a CEL!

 

I haven't ran the codes yet, I need to

 

Could be TPS, dirty IAC valve. Have you done the fuel pump ECU mod. If not I would do that first then work on the other things.

 

Ok thanks, what exactly is the fuel pump ecu mod?

 

Follow these instructions. Very easy

https://www.clublexus.com/forums/perf...tures-faq.html

 

Once you try the Fuel Pump ECU mod, if it doesn't work, I'd go to the TPS. I'd set it to spec with an ohmmeter. Your TPS could be out of spec. IMO, it look's like a TPS issue...but FIRST, pull the codes!! You don't wanna be replacing parts randomly hoping that they will correct the issue.
BTW, my CEL on my SC doesn't work.... It could be a long list of stuff, just pull the code(s) and go from there.

 

pull the cel and post it back up here before doing anything else, unless you want to do mods semi-randomly hoping one of them will work, which is plan B when there is no cel. Fortunately, you are still game for plan A.

 

Hey guys, I seafoamed it yesterday and changed the oil. This helped my car run better but it still didnt idle. This morning I started it up and same thing, However after about 2 minutes I got it to idle about 400 RPM. Then it just climbed up to 1,000 and stayed their. It now runs and idles perfectly. Think the seafoam did anything?

 

check if intake coupler is torn.

check the CEL. would be easier also

 

check CEL, then reset the ecu, in that order. report back on cel.

 

The seafoam probably did do something if what you say is true...pull the CEL code then report back to CL!