About Jeep Grand Cherokee Laredo! Catalytic Converter? ?

Question

I have a 1996 Jeep Grand Cherokee Laredo, I don't know what is wrong with it :( Let me start off my saying what I know. The jeep turns off while warming up,idling, gaining speed, or at a traffic stop.
I know for sure it isn't the fule system or my battery. I bought a new battery and had the fuel presser checked.
I was told it was my muffler, cause my muffler where it meets the pipe had dark wholes all around. I drove three days fine did not turn off at all. Yesterday While I was driving around 40mph I heard some sort of a loud popping sound Then a few Seconds later I hear a louder pop sound, Then the jeep died, so I pulled over and looked under the car, what I noticed was my New muffler had a dent inside of it like something inside popped and made my muffler "fatter" from the top and bottom of it. A few seconds later I turned it on with the engine or something making hesitation.
I don't have any clue whats wrong with my jeep. And another thing at times when the popping sound begins the jeep has turned off then rapidly turned itself back on.
My check engine light stays on AND when the jeep dies my Check Gages light comes on.
I put in a diagnostic computer in and it says:
P0420
CATALYTIC SYSTEM
EFFICIENTLY BELOW THRESHOLD
(BANK 1)
What does that mean? A sensor? Cat?

By the way I've added new spark plugs and a fuel treatment.

Answer 1

The cat is plugged and the platinum isn't working any more, it needs to be replaced, you can buy generic as long as there is room for the O2 sensor.

Answer 2

Jeep Grand Cherokee Catalytic Converter

Answer 3

Good description of what happened. The popping is too much fuel exploding in the cat, which is why it's ballooned.out.



You DO have a problem with the fuel injection system - it's running too rich, and dumping raw fuel right through it into the exhaust where it builds up and explodes.



The Codes don't really say exactly what is broken. They can only pop up because the computer is reading the electrical signal from whatever sensor is on that circuit. If the voltage is too high or low, it trips a code. It cannot ever pinpoint any broken mechanical part, it can only read electrical signals. Since OBD codes are a generic universal output, what can cause the problem can be considerably different from one car to another.



Likely the computer is being sent a bad signal from a sensor, and can't adjust the fuel ratio correctly to prevent the raw fuel getting in the exhaust. The first suspect would be the O2 sensors. A dealer level diagnostic - not just a parts house code reader - will be necessary to find and fix the fault. It still takes a mechanic trained on that make and model to diagnose a problem - not a machine. That doesn't even happen in jet aircraft, it's one of those Hollywood plot devices that moves the movie along. Real mechanics still have to test things with volt meters and know what to look for.



It will not get better on it's own, it will just keep exploding catalytic converters. It's cheaper to fix it right than keep shelling out $100's every time one goes off.

Answer 4

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RE:

About Jeep Grand Cherokee Laredo! Catalytic Converter? ?

I have a 1996 Jeep Grand Cherokee Laredo, I don't know what is wrong with it :( Let me start off my saying what I know. The jeep turns off while warming up,idling, gaining speed, or at a traffic stop.

I know for sure it isn't the fule system or my battery. I bought a new battery and had...