Justinsc4

Hey guys this morning I started up 1994 sc400 and at first it was idling fine as it always has then once the temp gauge reached that first mark the Rpms dropped to almost stalling, the engine was shaking like a bad misfire. Drove it a little bit it had no power at all. Brought it back and it started smoking white from where the cats are. Checked them and they were red hot. Shut the car off and let it cool down started it again once it was cold for a little bit and it definitely smelled like rotten egg out of the tail pipe. 02 sensors were recently replaced. Whenever I go to shut the car on now same issue it idles terribly and shakes. I haven’t driven it since. Clogged cats? Bad coils? Car has 220k miles

Ali SC3

iTrader: (10)

Usually a bad coil when that happens. Check the coils, there are lots of threads on it do a search for it: SC400 bad coil

Justinsc4

I’m assuming I’m gonna have to replace the cats right?

Ali SC3

iTrader: (10)

Not unless you have been driving it like that for a long time, if it just started happening you probably didn't destroy the cats yet.
I would fix the coil issue first and then see how it runs and if it is still smoking out the exhaust at all.

Justinsc4

That is the plan I will let you know how that turns out. The white smoke I was talking about in the first post was actually coming directly from the cats not from the exhaust. When I opened the hood a bunch of smoke was coming down by the manifolds from the cats. I checked under the car they were glowing red. I only drove it a very very short distance before they started smoking. Thanks for the help