Emackny

iTrader: (6)

Hey Guys,
First and foremost, I want to say that this site is THE BEST site for getting info on Lexus cars. Great job fellas. I dont post too much.. I guess you could say I just browse mostly. As I learn more about my car I will post more.

Heres my issue.. I have a 92 SC300 with 70k. About a week ago I started to experience rough idle and white exhuast with a smell of unburnt fuel. It would go away as I pushed the gas. The car died on me so I had it towed to my house. I changed the plugs, cap, rotor, and wires. while doing so I noticed the #5 plug had some carbon build up on it. The throttle body had tons of carbon build up as well but I was told by Lexus thats what happens to a car of that age, it just needs to be cleaned. Anyways the car started after plugs and wires were installed. Now the hesitation is constant. Sounds like Im running on 5 cyl.

I took the car to a local gas station for diagnostic check (big mistake). They told me that the #5 injector shorted out and also grounded out my ECM. $2000 to fix I thought to myself, better get another opinion. So I called lexus and the tech told me that ECMs on the sc rarely go bad and if it was bad the car would not start period. I figured I'd have the car towed to Toyota of Irving to see what they say. There gonna call me on mon with the results.

Here are some of my thoughts:

Headgasket- The car only has 70k! I checked the antifreeze (green as can be) and the oil is normal color.
TPS- Maybe.. Not sure. I dont think exhaust smoke is a syptom of a bad TPS.
Mass airflow sensor- nope
Fuel pump- checked (good)
Timing belt- Not sure.. (Looks to be in good condition but you can never tell by just looking)
Fuel Filter- nope

Do any of you have an idea as to what is going on?? Your insight would be much appreciated.

By the way I searched this whole site for this problem. No real answers.

O. L. T.

iTrader: (17)

check the intake tube from the MAF to the intake and inspect for breaks, cracks, or other leaks.

Emackny

iTrader: (6)

Thanks for the reply...

Already done... The rubber piece from throttle body was cracked from age but I replaced it.
No change.

dganapol

I had the 42.5 mph hesitation (stilled not cured). During my timing belt change I adjusted the TPS. I did not adjust it right the first time and when I started the engine it did not want to run. Because of all the things I had just worked on Belts,rollers,WP,Rotor,cap,wires you name it, I thought the worst. As it turned out I re-adjusted the sensor and everything is working well. The adjustment is in the book. If you want information on how to adjust let me know.
David 95 SC400

Emackny

iTrader: (6)

Man.. I wish that was all I needed but the white smoke has got me worried.
Thanks David I'll keep that in mind.