Sc400 engine problems

[mpcgta]

1994 Lexus SC400 160,000 miles
First time it has given me problems and all I do to the car is change the oil everything else is stock.

During the last Ice storm a few weeks ago I had my car outside. In the morning I started it up and let it get to operating temperature which it did with no problem. That night I again started the car but it had some problems....

1. When it first turned over its idle was about 500 Rpms and the motor was vibrating alot.

2. When I gave it some throttle the RPM would climb with the vibration but when the gauge got to 3000RPM it would shoot right back to 0 while the motors RPM were still climbing. blue/gray smoke is also coming out of the exhaust.

3. When driving there is a significant decrease in engine performance the RPM sounds strong but it feels as if it is not powering the transmission.

4. The Cat is also working hard cause its smoking out the tail pipes and smelling like rotten eggs.

5. The engine is also, while running expanding and making those ting ting sounds that usually happen after you shut off the car.

My thoughts...

1. Compression problem- Cracked block or busted piston.
2. To rich of an air fuel mixture- Computer/ MAS problems.

Thanks Michael

[5speed]

sounds like the headgasket might be blown and the engine is pulling in mass amounts of oil and burning it up

[mpcgta]

Ill check that and let you know

[5speed]

You seem to have all the signs and probably worse problems to be found.

[seanrg1116]

any CEL??

[mpcgta]

What is CEL?

[Sunkenkarma]

Check Engine Light.

[mpcgta]

Nope The CEL has not come on at all.

[5speed]

I would say have a mechanic look at it, whether they are doing it as a job or not. Somebody who knows what they are doing.

[speedminded]

1994 Lexus SC400 160,000 miles
First time it has given me problems and all I do to the car is change the oil everything else is stock.

During the last Ice storm a few weeks ago I had my car outside. In the morning I started it up and let it get to operating temperature which it did with no problem. That night I again started the car but it had some problems....

1. When it first turned over its idle was about 500 Rpms and the motor was vibrating alot.

2. When I gave it some throttle the RPM would climb with the vibration but when the gauge got to 3000RPM it would shoot right back to 0 while the motors RPM were still climbing. blue/gray smoke is also coming out of the exhaust.

3. When driving there is a significant decrease in engine performance the RPM sounds strong but it feels as if it is not powering the transmission.

4. The Cat is also working hard cause its smoking out the tail pipes and smelling like rotten eggs.

5. The engine is also, while running expanding and making those ting ting sounds that usually happen after you shut off the car.

My thoughts...

1. Compression problem- Cracked block or busted piston.
2. To rich of an air fuel mixture- Computer/ MAS problems.

Thanks MichaelCheck the oil? Is it clean or milky or smell like coolant? My guess clogged cats...

[5speed]

Check the oil? Is it clean or milky or smell like coolant? My guess clogged cats...
That very well could be the problem also, but normally the CEL would come on. Check the the consistency of the oil and jack up the car on both sides if you can and check the catalytic converter. Pull out a spark plug and poor a small amount of oil in there and then put the plug back in and fire it up. Check under the car to see where the problem might be.

[Barefoot]

4. The Cat is also working hard cause its smoking out the tail pipes and smelling like rotten eggs.

got to love it when people answer there own question in the question.

u got a bad cat.

[mpcgta]

My mechanic has ruled out all ideas given. Cat is good, no blown head gasket, engine is just fine, the computer itself is just fine and he cannot find any problem codes. what else could it be any censers he should check?

[cwhiteboy]

If your mechanic needs more ideas from people on here, then I would recommend a new mechanic.

But just for shits, I would as well question the cat. And your CEL might not come on for the converter, being as it is OBD-I.

[Jaimecbr900]

Sounds like the cat to me. If you have no CEL, it's not going to be a sensor or MAF.

[Barefoot]

ill saw it again this is a classic bad cat situation.

[ilbcnu123]

a bad cat doesnt cause the engine to smoke does it?

what i would do
-compression test
-leakdown test
-check oil for coolant
-check coolant for oil

[Barefoot]

a bad cat doesnt cause the engine to smoke does it?

clogged cat will depending on how bad the clog is.

[ilbcnu123]

clogged cat will depending on how bad the clog is.

seems like the OP experienced this problem all of a sudden. i cant imagine the cat became clogged that fast.. regardless, perform the inspections i listed and it will clarify some things