[03Black2v]

So lately I've been getting around 80-100 miles on basically a full tank. I have no idea what's wrong with it. It does feel sluggish, so I'm thinking it could be clogged cats?

I did an maf test, and when I unplugged it, my car still idled so it could be bad too.

Is there anyway to test if you have clogged cats without taking it to a dealer or shop?

Thanks.

[03Black2v]

I have also started to hear a ticking sound when idling, possible exhaust leak?

[p4ndiamond]

Check the oxygen sensors. sounds like you are dumping fuel. I mean basic things to check are

O2 sensors
Wires
Plugs
Sensors.

How does the ticking sound ?

[N20zuki]

Is the CEL on?

[SON1C]

i'd replace 02 sensors plugs wires fuel filter

[03Black2v]

Originally Posted by p4ndiamond Check the oxygen sensors. sounds like you are dumping fuel. I mean basic things to check are O2 sensors Wires Plugs Sensors. How does the ticking sound ?

How would I go about checking all of this? And its not very loud, but you can hear it if you're sitting there. I first heard it in mcdonalds.

Sent from my dog.

[03Black2v]

Originally Posted by N20zuki Is the CEL on?

Nope.

Sent from my dog.

[p4ndiamond]

Pick up two motor craft O2 sensors from rockauto.com. OEM are best and they have them dirt cheap.

Forgot that you have COP so it should not be an issue unless you are getting am misfire.

Plugs should just be changed and gaped if you never did before. its easy to do.

[03Black2v]

Changed the plugs not too long ago and they were gaped.

[Eagle2000GT]

My best guess is clogged cats. I had a Chevy truck that had clogged cats. It is surprising how much fuel the computer will pump into the motor when that happens.

[03Black2v]

Anyway to check to make sure its clogged cats? Might just call the dealership tomorrow and have them look.

[1996 GT]

Unbolt your mid pipe from your cat back. Hit each cat with a rubber mallet, usually you can hear some clunking and what not.

[03Black2v]

Still getting terrible gas mileage. Haven't had time to check any of this lately though. Been really busy. I average around 60-70 miles on 3/4ths tank... It's that bad. I'm gonna call the dealership and tell them that I'm getting bad gas mileage and need them to look at it. I hope I can find out whats wrong, really annoying have to put $20 in this damn car every week just to drive to school and back.

[Cabikejumper]

Take it to an exhaust shop. They will drill a hole, and test it. Shop did mine for. 10.002-4psi is what they said it has to be around.

If you have an exhaust leak, I'd bet it's a o2 problem. When I had a exhaust leak I'd suck gas out. I put quiksteel around the leak and sealed it. Got better mpg too.

[Shaun03GT]

I was curious to see how much gas I got out of a full tank. It was at about 180 miles at 1/8 of a tank. Don't know if thatw good for my set up?

Op, probably needs a tune up. Replace the fuel filter, air filter, spark plugs. Check the rear o2s. Clogged cats usually give a bad odor, so if you don't smell it chances are their fine.

MAF isn't bad. Car can run without the maf plugged in, it'll just rely on the front o2 sensors basically.

[03Black2v]

Thanks Shaun. Replaced the air filter, and spark plugs already. I'll check my fuel filter tomorrow and see how dirty it is and probably go get a new one. Reccomended brands?

[Notcho]

If the catalytic converter(s) is/are blocked, you probably wouldn't even get a code.

If you're not getting a code, other stuff like your O2 sensors are probably good. The computer checks for issues with them constantly... if one of them isn't reporting acceptable measurements (which it wouldn't if it were defective), you will get a code for it.

For cats, they can fail in a few different ways. First, you should know they are essentially a can with a honeycomb shaped catalyst (usually an alloy containing platinum) inside, which is wrapped with a fiberglass insulation so it wont rattle inside the can.

If the fiberglass burns out, the cat will rattle loudly. It will not effect runability or fuel economy in any way. You will probably get a code, because the raw exhaust is going around the catalyst (honeycomb platinum part) without being burned, and the O2 after the cat is detecting the raw exhaust gasses.

If the catalyst honeycomb breaks apart and turns sideways, it will create an effective air block, and will also hinder performance. It will probably rattle like hell, because at this point there are chunks of metal rolling around inside the "can." You will probably get a code here too, because exhaust gasses are going around the catalyst instead of going through it.







If you have mechanical engine issues, the cat could clog up with oil/other crap, which could keep it from working correctly. Again, this would probably throw a code.
















Or, if it gets super hot, it could melt itself shut.



In that case, you probably wouldn't get a code, at least not for the cat. Because technically, the cat is still working... at least part of it is. The exhaust gasses still go through the open part of the cat, and is cleaned up, so the O2 sensor after the cat would detect clean exhaust, and wouldn't throw a code. But, with so little exhaust flow, it would run like shit.