300e is totally confusing me

I cut the catalytic converter out and the car starts up, but only runs for about 45 seconds then cuts out. It will start up but chug again. When it runs for the 45 seconds it runs fine. Be advised I have a bypass test
hookup going through both tailpipes. The reason why I cut the cat out was because the cat was all black in side and appeared all black. I ruled out fuel is not the problem anymore, neither is spark. Could it possibly be the EGR valve or something else? -THanks Chuck 89 300E
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What did you do with the o2 sensor ?. Is it still in the system?

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The o2 sensor is dissconnected from the system....-
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I actually started the motor without the exaust hooked up ofr about 10 seconds the other day. Maybe I should run the motor longer with the exaust system DCd? If this is the case and it runs longer than a minute or so, maybe i should just replace the mufflers as well...-Thanks- Charles Granger
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The motor starts easily? Or hard?
Then runs well for about 45 seconds and stumbles to a stop OR stops as if the key is turned to OFF?
If, when it starts and runs well, you rev the engine to say 3,000 rpm and hold it there, does it quit sooner than when it runs at idle speed?
If so, can you (briefly) run the motor without the mufflers? (This is a neighbor question, not IF it can be done.)
Running it without the mufflers would empirically test the mufflers' flow or blockage.
If it keeps running without the muffler, then the muffler is blocked and is choking the engine.
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If i keep the motor at a 2000-3000 RPM load its stays running a little longer. Running the motor without the mufflers is not a problem. I lived 1 block away from a really loud fire alert siren. -Chuck
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Well i ran the car without the exhaust system hooked up and the car did the same thing.....cut out after a minute. Maybe its time for the mechanic...
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OK, Chuck has proved that neither the CATS nor the mufflers are blocked, so the possibility of a blocked exhaust is eliminated.
The ignition has been renewed, the fuel supply system checked up to the engine. The fuel regulator replaced or rebuilt? Chuck, which?
That leaves the engine control system, including the over voltage protection relay which was also replaced some months ago.
The O2 sensor suggestions are valid, IMHO, not because I KNOW so, but what else could be causing the motor to quit running after only a minute? (Fuel filter was replaced.)
www.oxygensensors.com sells an O2 for this car for $45 (Walker) to $120 (Bosch), I'd buy the Walker because the O2 isn't KNOWN to be bad, just suspected so.
Before taking the car to a shop I suggest you list everything that's been replaced or proven to be OK and post it here, someone may have a fresh idea.
Tom
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