The most important component of the exhaust of a car is its catalytic converter.
The catalytic converter is found in the exhaust line between the muffler and the engine, and its basic purpose is to maintain an efficiency level required by the state to limit pollution while reducing the emissions from the exhaust. It has some precious metals inside it known as catalysts which react with the pollution before it can be released to the atmosphere, converting them to less harmful gases hence making the system environmentally friendly.

Bad catalytic converters are terrible for the environment, driving with a bad or no catalytic converter not only means you are driving around transmitting various harmful gases to the air, but also the passenger area of your vehicle. While your car can still give you drives as long as you want even with your converter going bad although, you will notice some rotten smell and smoke every time you drive. Your car will stop working efficiently but would not stall completely because of the bad catalytic converter.
The only way your bad catalytic converter can stop you from driving your car is through police. If you get caught with a bad catalytic converter which is, of course, a threat to the environment, you can get charged with fines, and you may not even be able to drive your or any other car before you get your catalytic converter replaced first. However, it may also stop you from driving if it becomes completely clogged, which only happens if you keep driving with a bad cat-con for a long time or it gets wrecked.
Content Navigation
Hints That Your Catalytic Converter Is Going Bad
Before keeping in mind that you are driving with a bad catalytic converter and considering some safety tips about it. First, you need to be sure about having a bad catalytic converter. Here we will briefly discuss how the engine will be dropping some hints of the catalytic converter going bad.
The engine’s performance will start to suffer, and it will keep worsening over time. Your vehicle’s pick will be the one having the worst time, and the engine will not be as responsive as it used to be. You notice a clear difference in stepping the accelerator of the car and being accelerated.

You’re driving around as usual, and there’s just so many rattling noises that are making you crazy, that right there is a clear sign that you don’t have a good catalytic converter. This is usually the noise generated from some loose parts within your cat-con. This is one of the most serious problems because the loose parts could eventually block your entire exhaust pipe and stop your wheels!
Finally, the easiest sign to apprehend is the smell of rotten egg and noticed the engine light turned on. Under usual circumstances, the catalytic converter converts the exhaust gases into harmless, odorless Hydrogen Sulfide whereas if it gets clogged up, the conversion is not successful hence you can smell the sulfur in the air which smells somewhat like rotten eggs. You can also undergo an emissions test to be sure about the bad catalytic converter.
How Long Can You Drive With A Bad Catalytic Converter
However the reasons to have a perfectly working catalytic converter in your vehicle are ample, from performing efficiently to conserving the environment, they still can be avoided if you want, but the usual answer here is “It can be driven as long as you want.” In fact, vehicles did not even come with pre-equipped catalytic converters until 1975, so if your car is older than that, it may not even have one. So, let’s dig a bit deeper into this!
A bad catalytic converter can be driven indefinitely and doesn’t hurt much depending upon your drive and the severeness of your issue. If your catalytic converter is slightly bad and the only destinations you ride to are close by, it is probably not a disaster for you, and you don’t need to rush and get it replaced or get it unclogged. Keeping in mind, you will have a significant amount of your money being wasted on the extra fuel being consumed, which keeps on increasing if the cat-con keeps on being plugged. The performance your engine will be delivering will also go downhill, so you need to be prepared for that as well.

If your vehicle is burning too much fuel, or “running rich” as some people call it, it may result in the inner fiber of your catalytic converter being burned. Essentially this wouldn’t keep your vehicle from running, but you will notice some smoke and observe a smell while you drive.
The worst-case scenario is faced when the catalytic converter gets too much clogged over time and stops operating and eventually leaving you stranded along the road. This often happens if the parts inside the cat-con get loose and jam the exhaust pipes.
Driving with a bad catalytic converter, your engine heats up far more than usual. Especially if you are going for longer trips, you should be looking out for this. Pay very close attention if the floor near the catalytic converter is getting very hot, or the whole cabin in general because however fewer possibilities maybe, a very high temperature around the engine could always make the vehicle catch a fire.
Last but not least, the area you’re driving around really makes a difference! Some countries require the vehicles passing the emission test. You don’t need failing these tests as the penalties are whopping and wish that you rather had your catalytic converter replaced.
Related Post: How to Unclog a Catalytic Converter
Being Cautious While Driving With A Bad Catalytic Converter
As we’ve already reached to a conclusion that you can manage things and drive even with having a bad catalytic converter, still we need to look at some safety precautions we need to have on our mind to avoid any discomforts.
Running the car without a proper functioning catalytic converter might make it run very hot. This increased temperature around the engine of the car may start a car fire in the worst case. This situation, however, is very less likely to happen and may only be faced when going on long trips. So what you can do is taking some breaks while longer drives to make sure it cools down enough to avoid any problems caused by overheating.

Eating up fuel is amongst the main characteristics of a plugged catalytic converter, and it might seem a bit insignificant to you right now but approaching longer trips, this could turn out to be something you need to be very careful about. The fuel tank will be going out a lot earlier than usual, and you might miscalculate the time when you need to refill it. So, driving on highways or areas with less filling stations around, don’t wait out for the tank to go low and get it filled before going below 30%.
Be sure to check whether the area you’re cruising has tight rules about having bad catalytic converters. If caught, you could be charged heavily, depending upon the state. So if the issue is known and the fine in your state is high, it might be in your best interest have your bad catalytic converter replaced as the fines are far more than the replacement cost and you won’t be able to drive unless you get it replaced if you’re caught.
Read Also: Top 10 Catalytic Converter Cleaner Review
Conclusion
Catalytic converters have been pretty crappy in the past but thanks to the ever-increasing tech, they are better than ever as well as very reliable. They are not something which wears off easily and is meant to go on for the life of your vehicle. However, there is no uncertainty when it comes to machinery, and they can go bad for one reason or another.
As of now, we have successfully answered the question of how long can we drive with a bad catalytic converter and we know the safety precautions to take while driving with it, I hope you still know why it may not be in your best interests to do so.
However, under certain circumstances, it might be advisable not to pay heavy amounts of replacement whenever you run into a problem with catalytic converters. One of the circumstances being your usual drives being pretty brief that the extra money spent on fuel don’t bother you and the law enforcement isn’t that strict about getting you caught. In such a case, it is probably preferable to go with a clogged catalytic converter instead of paying huge replacement costs. As now you already are aware of the period you can go with a clogged cat-con and the things you should care about, I hope you are pretty good to go!
Hello David, I read your article today because I think my Cat is having problems. I have a 2004 Ford F-150 and it’s at 116,000 miles. It just started vibrating last year in the summer, and the mechanics noticed it, but didn’t give me any clues as to what would be causing it, so now that it’s having a shift problem at times bet 3-4 gear, and a rough start up, leads me to beleive it could be this problem. Given these signs, do you think I would have a chance of waiting to get it fixed in October, or should I worry now? I mostly drive in town 1-2 times a day short trips.
Hi Carol, short trip not a big problem but you are losing some fuel and it’s risky to drive because you have to take break while in a long trip. Also, sometimes you may have to handle police if your city police bother about this. But it’s replacement cost is bit higher. you can wait for October if it won’t create problem too much but change is the best solution. You can ask your mechanic because he/she checked your can properly and knows the problem very much because he/she informed you about it. It could be something else although signs seem to catalytic converter problem. Thanks for asking me.
Hope you can help me I drive a 2004 Nissan Maxin SL and it became to lose speed when I’m driving. Someone said I need a catalytic converter but I don’t smell and raw eggs I don’t hear any noise it just lose speed when I’m driving . If you can help me with this problem. I glad appreciate it. Thank you I’m on a fixed income is there any hope for my car.
i need help my 2004 Nissan Maxin Sl is losing speed when driving . Help me someone says that I need a catalytic converter but I don’t smell any raw eggs it just losing speed power very slow when driving.. Thank you
Hi Dot Ramsey, your car losing power or only losing speed?
losing power i believe he’s tryna say. i’m having the same problem when i steph on the gas feels like i’m forcing the accelerator to catch up
Good morning David, I have a 2000 Ford Windstar, I have been told that I had a bad cat, it was a few years ago and the reason being the o2 sensor 2nd bank 2 code constantly on. Just a little history. About 6 years ago I replaced the engine, afterwards it was running a little rough and I asked for the mechanic to use that spray to clean out the idle air control valve, about a mile later the code went off, they kept trying to clear it but it never would, this went on for a couple years. So at this time the mechanic said the cat was bad, he eventually did get an o2 sensor that worked. Fast forward another 2 or so years, different mechanic, car running rough, I asked them to clean out the idle air control valve, I totally forgot about what previously happened, and yes, within a mile of leaving, the code went off. They changed the o2 sensor and it actually worked for about a month, then the code went off, as well as another sensor, I don’t remember which one, and it doesn’t always show on the computer. In August I replaced the alternator, since then the car had been running really bad, headlights flickering, issues with the windows, and issues starting, as well as severe surging. The other day two mechanics said the alternator and battery were fine, the second one cleared the code, which of course came on again, and the surging had stopped, and the car was actually running well for the last few days. This mechanic and I talked extensively about the cat because of the issues, and the o2 sensor.So at the same time I have been having starting issues which had started just after the alternator was replaced, I will try my hardest to describe that.Normally, my first start of the day, there seems to be a jump when the key is first turned, but it starts fine, sometimes, after I have driven it, it will crank and sound low, and it feels like it wants to stall, and it has stalled a couple times but started right up after, sometimes it will even out on it’s own, sometimes I give some gas. Quick note, the battery does occasionally say it’s not charging, but no one is concerned with that. Yesterday, I was out, drove in the city to a few stores, turned the car off twice, second time the car wouldn’t start, cranked made a couple sounds, then stalled, second time same thing but the sounds were a few more, I pumped the gas (this is what I was told to do a few weeks earlier) and it tried starting a little longer, then I waited about half a minute and stepped on the gas and started it, it was trying to start, then started. The problem is the sound it made, there’s a man who has a video, and he made two sounds, one was like a battery issue, which was a drawn out sound, and the other he said was a fuel issue, which was more sharp. My daughter said it was more like the first, I think it was more like the second, but I can’t remember. If I’m allowed I can send you the link tot he video with the sounds. I’m so sorry this is long and probably confusing, but I think the cat issues have finally destroyed my engine. What do you think?
It’s too long Ali and totally confusing. You can send me the video link. Also you can take it to a good mechanic because real time observation always better than others and your description saying many things (also confusing). Don’t take it to a low level mechanic because already you messed a lot. Have a good day. Hope you will successfully repair it ASAP. Thanks.
I have a bad converter my car ran hot will it start up if I let it sit