Car Issues, Need Some Advice

[Mr. DS]

Are there any mechanics on the board or people knowledgeable with cars?  Heres the story.  I have a Volkswagen Jetta and I've brought it in a few times for sputtering/stalling problems.  The place I brought it the first time did a tune up and replaced spark plugs/wires.  Weeks later it acted up again an the computer said it was the coil which added to the last issues ran me about $1000.  The car is running good but the engine light has been on twice.  Both times the mechanic said it probably could be the engine trying to recognize the new part.  However the last time I had them tell me the code which is 420 'Catalytic Converter Not Working To It's Efficiency'. 

They popped the code off again for me but now I'm beyond concerned.  I don't have any more lungs to sell for car repairs if that converter goes.  I guess my question is, what the hell is going on with my car?  Am I getting taken for a ride by the mechanic?  The place I go to is rather reputable and have been honest with me before about work I don't need done. 

[Jack]

I guess my theory would be that if the car was stuttering and stalling, and the coil was bad, perhaps enough voltage wasn't being sent to the plugs and the fuel/air mixture wasn't being ignited properly.  It's possible that if enough unburned fuel got into the catalytic converter, it may be partially clogged with soot or something.  I dunno, my theories are almost always wrong    If the error code doesn't come back, I guess I wouldn't worry about it.

[The Burgomaster]

I had a Dodge Charger in the early 1990s that would just die suddenly while I was driving it.  No sputtering, no warning . . . I'd just be cruising along and suddenly the car would lose power, the tachometer would fall quickly to zero, and I'd glide into the breakdown lane.  Sometimes it would take several minutes before I could get it started again.  I brought it to a local mechanic who changed the spark plugs and did a bunch of other things, but he could fix it no matter what he tried.  So, I brought it to a Dodge dealer and explained the problem to the service manager.  In about one second he blurted out what the problem was (I can't remember what he said).  I left my car there over night, picked it up the next day, and never had that problem again.  So now, I always bring my car to the dealership for service, even if it costs more than a local mechanic.  

[ghouck]

I guess my theory would be that if the car was stuttering and stalling, and the coil was bad, perhaps enough voltage wasn't being sent to the plugs and the fuel/air mixture wasn't being ignited properly.  It's possible that if enough unburned fuel got into the catalytic converter, it may be partially clogged with soot or something.  I dunno, my theories are almost always wrong    If the error code doesn't come back, I guess I wouldn't worry about it.

That'd be a fairly easy one to deal with: Fill it up with the cheapest gas it is meant to run on, not the higher octane ones, get her out on the highway and drive it a bit hard for a while, I'd put 60 miles or so of fairly hard driving on it. Lower octane fuel will actually burn a bit hotter, between that and running it a bit hard will help get some of the crap out of the CC. 

[Mr. DS]

Update, I had it looked at and its the CC.  However, through the EPA the dealer has to replace it for free.  As long as its firing out the code (check), under (80k) and the CC is unaltered (check).  Hopefully things are looking up. 

[Javakoala]

I'd say, get a bicycle.

But what do I know?