How to tell if my catalytic converters are bad?

[MyEarsHurt]

Well, here is the deal, ....

Problem #1: I bought my stang from this kid, and when I bought it he told me he had a flowmasters catback exhaust and that because of that there was a check engine light. I didnt know that much about it so I said whatever, I had the code pulled and it was for the 02 sensors. I didnt know much about exhaust at that time, and so I ignored the code for a while. When I actually learned that the flows couldnt be giving that code because I still have all my o2 senors, I quickly replaced the bad sensor.

Problem #2: Being that the check engine light was on all the time, I didnt know this, but I had a misfire in 1 cylinder, for WHO KNOWS how long. I fixed this problem by replacing all the plugs and plug wires, and now I have a whole other issue.

It seems like if I push on the gas to try to maintain high speeds (like 45-55 mph) my car gets really sluggish, and then I hear a popping noise, and its fine for a few miles, then it will do it again. Could this be bad catalytic converters? I really hope so, because the popping noise is REALLY awful and if it was something as simple as replacing the midpipe, I would be very pleased. Anyone have any ideas? Could this be my problem, what are the symptoms of a bad cat? Thanks in advance, man what would I do without this forum....

 

[ADRENLN]

do you still have a check engine light? if its the cats that are bad, you would.

however the check light could be anything, as you found out.

as far as the poping i dont know but this dont sound good ,and neither does no power.

bump

 

[MyEarsHurt]

There is no check engine light on anymore, so does that mean I can rule out the cats? Or could they be bad without getting a check engine light?

 

[70stangcoupe]

If they were bad, you'd get a CEL.

 

[MyEarsHurt]

dang, I have no idea what it is then, time to pay a mechanic....

 

[AirWolf87]

yeah the O2 sensors are VERY sensitive...if your cat was bad it would give you a CEL right away. Does the car buck at all when you hear that poping sound? If it does, it could very well be a fuel problem...start by replacing your fuel filter then go from there. If it just pops and it doesnt buck or jerk at all....got me...get professional help.

 

[MyEarsHurt]

yeah the O2 sensors are VERY sensitive...if your cat was bad it would give you a CEL right away. Does the car buck at all when you hear that poping sound? If it does, it could very well be a fuel problem...start by replacing your fuel filter then go from there. If it just pops and it doesnt buck or jerk at all....got me...get professional help.

I replaced the fuel filter last week
Didnt help at all...

 

[huesmann]

Go get yourself emissions-tested.

 

[70stangcoupe]

Yeah, just one of those things, time to shell out the dollars. Hope it's nothing too serious.

 

[COramprat]

Check your plug wires and plugs to make sure you haven't fouled one. I accidently left one loose one time and it started arcing in the boot causing the car to run sluggish. It would up fouling the plug. I pulled it and put a new one in, making sure I had the boot on tight. Ran fine ever since.

 

[MyEarsHurt]

Check your plug wires and plugs to make sure you haven't fouled one. I accidently left one loose one time and it started arcing in the boot causing the car to run sluggish. It would up fouling the plug. I pulled it and put a new one in, making sure I had the boot on tight. Ran fine ever since.

Yeah I checked all the plugs and plug wires first thing, everything was secure and in place...too bad it couldnt have been that simple.

 

[AirWolf87]

Yeah I checked all the plugs and plug wires first thing, everything was secure and in place...too bad it couldnt have been that simple.

maybe your timing is off. If its not fuel, it sounds like a spark issue. Make sure your computer is not messing up your ignition.