Exhaust afterfire “bubbles”

Hi Ik I sound like a dummy posting on this page about my stock 2010 Ford Focus. However after I backed into a telephone pole(again sound like an idiot but I’m actually am a good driver and desperately needed to find a washroom and the telephone pole is in the Center of that driveway) my exhaust came unhooked at the flex pipe and now it doesn’t do anything. I did notice it was a bit bubbly before that happened but after it did I noticed it starting to do it for longer whenever I let off the gas. It does it about twice as long now as it did when I first knocked the exhaust off. I’m just worried that it may cause my engine to blow up if it’s a timing issue as it is a beater and I do beat it (young and dumb as you can see) if it’s just popping and there isn’t a bigger issue that would be catistrophic to my engine I’m not worried. It is getting way worse mileage than it did before (5-6l/km before and 8-9 since I first noticed any bubbles even before the exhaust came unhooked. Got a new air filter last week and it helped some because the old one was pretty dirty. If anyone could put my mind at ease it would be greatly appreciated

I won’t put your mind at ease, just gonna make it worse, unfortunately.

A broken exhaust pipe can make you very sick or kill you if it lets exhaust gas into the car. Whatever is actually happening, the bubbling, as you describe it, doesn’t matter nearly as much you breathing odorless carbon monoxide from the exhaust gas.

Get it fixed or stop driving it until you do. That is my advice.


“Bubbling” in old cars (pre fuel injection) was often the result of partially burned fuel continuing to burn after it was exhausted from the engine. Not so common today with precisely metered fuel and emissions controls.

I don’t know the mileage and I’m assuming you’re not getting a code but have you done the required maintenance including the spark plugs?

It’s efi and I personally haven’t done spark plug maintenance to it. 192xxx kms on it and it’s not throwing any codes at me. I’m not concerned if it’s only affecting mileage I can live with that. Just as long as I can cat another month or two out of it

I always get my oil changed on schedule and like I said I just replaced the air filter a week ago for the forst time in 2 years. I’m not sure how new the filter was when I got the car

Well if your goal is only a month, just roll down the windows and don’t leave it running in an enclosed space or next to a building air intake and you’ll probably be OK.

An alternative is a set of new plugs, will probably cost under $10, and can be replaced in under an hour by anyone with basic tools and skills, or for a few dollars more by a real mechanic.

On the other hand if it actually is running rich and you do nothing, you’ll eventually damage your cat converter by clogging/overheating it (don’t park near any high dry grass) and you may even discover what a backfire can do to your exhaust.

As someone who has been sickened by a exhaust leak I can assure you that you do not want that to happen . Fix the exhaust .


Symptoms of CO poisoning include headaches, nausea, confusion and as you approach death your face gets red like a sunburn. You essentially build up CO in place of oxygen in your blood cells and die from lack of oxygen. If you get emergency care soon enough, you can survive it but you will be on oxygen for a couple of weeks at least.