Well freaking fruitty doo...It's doing it again...
 

Hello all,

'93 SC400 131K. No CE showing. Yesterday, the wife left the car running with the AC on while she went into the store. She was in the store for about 30 minutes. Had no issues driving back until about a block from the house. (After driving on highway 20 miles) stared running rough again. Has been running rough all of today.

MORE INFO - Wife just told me that the car is using an unusual amount of fuel. I'll search forums too. Thanks.

I replaced the air filter as a precaution. Could the sitting idleing caused a problem? Any ideas? Can't figure why it was running fine for a week then all of a sudden ugh.

Appreciate any direction.

LMA

Unplug the MAF and see how it drives.

wow i'm surprised it didn't get stolen. check or change your spark plugs, wires, cap, rotor and fuel fitler.

I'm not sure letting a car idle for 30 minutes unattended is a good idea...

we have a 93 sc300 here doing this same thing as well... either an injector started sticking open, or you may be dropping spark. i would let to run, start to run rough, and tap the injectors with a screw driver.

traced down our problem yesterday on the sc300. it's a 93 2jzge automatic.

injectors were wigging out with the key on. very excited and erratic ticking while key on, engine off.

traced the circuit back inside the ecu. good continuity between ecu and injectors.

broke the ecu out(passenger floorboard. peel the carpet back from the front, remove the black cover, and you see the ecu. remove the harness, loosen the mounting nut, remove the ecu.

opened up the ecu for a quick peek, and noticed a rather large burnt spot...

went to the local micro electronics store, bought the new capacitor, and soldered it in.

car runs like a champ now...

this was what i found/did. your scenario may be a little different. hope this helps you though.