Oldsmobile/Buick Repair: 1989 Buick LeSabre, 3800 engine, buick lesabre

Question
OK - I am a female, but will try to be a prescise as possible.  I have a 1989 Buick LeSabre, 3800 engine, that has had a problem for the last three years.  Somehow, (and this is my question), the exhaust is directly related to a control module problem.  I personally think it has a clogged or bad catalytic converter (but my husband doesn't agree that this would cause the problems we have had.)  About 3 years ago, we had a problem getting the vehicle home.  A 30 minute trip ended up taking 2 hours.  The vehicle would run for about 10 minutes, and then shut down.  Once it would cool off, it would start again, run for about 10 minutes, etc.  Finally, the car backfired, blew a hole in the muffler, and ran perfectly fine all of the way home.  I think that at that time, whatever was clogging the cat converter blew out.  (And / or there was less pressure on the engine without the muffler).  Although it did not die anymore, it still had running / timing type issues.  My husband changed the control module, along with other timing components, and it ran fine.  This same thing has happened a total of three times.  The second time - same thing, the vehicle would die, have to cool off, and finally backfired and blew a hole in the muffler - then quit dieing.  It is currently doing the same thing again.  The car was running fine, and we had a new muffler put on it.  At that time, it started running bad again, like a timing problem.  It jumps and has no power in 1st & 2nd gear, especially going uop hills.  It was running quiet right after the muffler was put on, and now it has opened up a small hole somewhere because it is a little louder, but hasn't blown a hole in the muffler yet.  My husband wants to change the control module again, but I told him to wait until we find out what is causing it to go bad.  He said that each time he changes it, it has like a jelly substance inside.  I know that if it were a cat converter problem, it would have the dieing problems when hot.  However, my question is how is that directly related to causing the control modules to go bad at the same time?  I also know that the backfiring is caused by a timing problem, but once that happens and it blows a hole in the muffler, it still has the timing problems, but it doesn't die anymore.  I just feel like the two are related, but my husband doesn't agree.  Please help me!!

Answer
Hello Tina,
If the muffler or converter is plugged, it will be plugged hot or cold. One exception is if there are flakes of rust inside the pipe, and there is a spark arrester, and the flakes stack up against it causing the plug, and then fall of when the engine is off, only to stack up again after it runs a while.
A plugged exhaust will cause the engine to act like that, but so will several other things.
It doesn't cost nearly as much to temporarily remove the muffler, as a module.
There is some heat dissipating grease that is supposed to be used on some modules to keep them from melting. See if it is recommended on yours.
A plugged exhaust can cause everything under the hood to be hotter, and could contribute to module damage.
The backfire could also be caused by rich fuel mixture getting into the exhaust system, and then finally igniting.
Hope this does something besides muddy the water.
Van