My '94 sc300 was running fine now all of a sudden it runs like crap, it runs like a putt putt now and has a strong gas smell and white smoke coming from the car any ideas of what it could be, at first i though it might be a bad catalytic converter but now i think it may be more serious than that. please help need ideas of what it could be.

 

Have you checked it for codes?


Reading Trouble Codes
If the ECU has detected a system malfunction, the check engine light will blink every .5 second. The first number of blinks will equal the first digit of a two digit diagnostic trouble code and after a 1.5 second pause, the second number of blinks will equal the second digit of same diagnostic trouble code. If there are two or more DTC's, there will be a 2.5 second pause between each. After all DTC's have been output there will be a 4.5 second pause and all DTC's will be repeated as long as the terminals TE1 and El of the data link connector are connected. In the event of two or more DTC's, indication will begin from smaller numbered code and continue in order to the larger. After all DTC have been recorded, remove jumper wire.


Then afterwards clear them and see if that doesn't help make it run better.

Clearing Trouble Codes
After service, the diagnostic trouble code or DTC's retained in the ECU memory must be cleared by remove the EFI fuse for approximately 10 seconds or more, depending on ambient temperature (the lower the temperature, the longer the fuse must be left out) with the ignition switch off. DTC clearing can also be done by removing the battery ground cable, other memory systems (clock) will also be cleared. If the diagnostic trouble code is not cleared, it will be retained by the ECU and appear along with a new DTC in future trouble codes. If it is necessary to work on engine components requiring removal of the battery ground cable, confirm no DTC's are stored. After clearing codes, road test the vehicle to check that a normal operation. If the same diagnostic trouble code appears, the trouble has not been corrected.

OBD1 codes:

info courtesy of http://us.lexusownersclub.com/forums...howtopic=37260

 

Ecu took a dump or blown hg, mine did that and it was the ecu, didn't find out till 2 motors latter...

 

have you checked if all the cylinders are firing. check cap and rotor. spark plugs and wires. sounds to me not all cylinders are firing. is it like a white bluish smoke. or just straight up white. also check ignition coil. just a thought. if all of those working. then yea hg can be blown. or like how these other folks said, ecu.

 

Any CEL illuminating?

 

Could be an ECU issue, could be a injector stuck open, ect we need more info.

 

Thanks for help had mechanic check it out and came to the conclusion that the valve seals are bad

 

That's not so bad then. Keep us posted on the progress.

 

headgasket, ecu, or fuel pum would be where I would start