I have a 1997 Buick skylark Custom. 2.4 liter- 4 cly.

The catalytic converter went bad. Glowed red hot. Took it to O'Riely's Auto. They did a scan.
It had multiple cylinder misfire and O2 sensor.

The converter was roached real bad. Chunks came out of one end. The O2 sensor was shot and turned sideways from the heat.

Needless to say, I replaced the converter and sensor. I also put in new plugs and on boots.
Engine seemed to run better.

However after about 5 minutes the new converter be

However after about 5 minutes the new converter be


Finish your statement.

Without your concluding thought, I imagine the Ignition Control Module (ICM) is failing. Remove the four bolts securing the aluminum cover to the coil packs and spark plugs. The ICM is mounted to bottom of the cover plate with three screws--simply remove and replace. Failing ICMs often allow unburned fuel to build-up in the converter, which eventually destroys it. Sometimes, the unburned gas is detonated, blowing the converter and exhaust system off the car.

Thanks.
My finished thought was the converter gets red hot again.
I spoke with a couple friends I know who work on cars.

They said the if the ICM was bad the car would not even start.

I will try that. The engine runs and sounds good. I just can not rid of the extra fuel being dumped into the exhaust and consequently the converter get red hot.
Thanks and God Bless

The problem is likely intermittent ICM failure, at this point, which allows unburned fuel to build-up in the catalytic converter. I'm convinced it's ignition system related. If the problem persists, after replacing the ICM, I would install new coils.

When not replaced, the vehicle could experience any of the following: no/hard start, long crank time, misfire, lack of power, inconsistent transmission shift points, spark plug fouling, catalytic converter failure, poor fuel economy, CEL/MIL illumination.

What did the old spark plugs look like?

Plugs did not look too bad. Number 4 was fouled and I think number 2.
Nothing crazy... but certainly needed changing.

After changing the plugs and boots, the engine ran much better.
Yet, it continued to dump extra fuel into the brand new converter.

I will be on tomorrow morning. I am hopeful this will solve the problem.

Thank you for your help and follow up.
God Bless Brother!

In my mind, the excess fuel is related to the originally reported multiple cylinder misfires. Misfires can also be related to poor compression and/or leaking intake manifold, which can be checked with the engine running and a spray bottle of water.

Ok, you have got my attention.
I spay the water on the intake... I am looking for what?
Mist blow back?

Any change in the sound of the engine, which would indicate a leak.

Hi GreaseMonkey,
You were one hundred percent on the mark. The ignition control modual
Was working intermittently. Replaced with a part from local bone yard.

Car is puring like a Kitty Cat. All engine lights, codes are gone. The transmission does shift smoother now as well.

Thanks for the help. May the new year find you in good health and blessed.
Thanks and God Bless.
Jim

Very nice job--you made my day.

For the new year, I recommend that you start using SAE 5W-30 full synthetic engine oil. It will help your engine last longer, perform better, improve gas mileage, and prolong the life of your new catalytic converter. I would also drop and clean the transmission pan and magnet, replace the filter, and refill with Valvoline Dexron VI, which is available at O'Reilly Auto Parts.