Need some help with a cat problem

[liers99]

My rig is a 2000 5.0 AWD. I have a check engine light and the code says the cats are bad (can't remember the number). Had 2 mechanics look at it and tell me it needs cats and it might, but I think there is an underlying problem. I also have a really rich smell coming from the exhaust, almost like raw gas. I suspect I have a blown lower intake gasket because I keep losing coolant. Not sure if these 2 issues are related or not. I just don't want to spend money on cats just to have them burn out again. Where do I start? Did some searching on here and haven't really found any answers.

 

[Flash]

One thing that ruins cats pretty effectively is running raw gas through them.

Apparently cats can be cleaned.....with soapy water. That is if they're not slagged.
No amount of washing will fix a slagged cat.

Google it or look it up on youtube. Haven't done it myself or know anyone who has.

 

[liers99]

So where do I start looking to see if i have a gas problem?

 

[1998Exp]

Get the actual codes and post them here.

So where do I start looking to see if i have a gas problem?

 

[JusTheUsual]

"Need some help with a cat problem" get a dog...ba dum tsss....

 

[JusTheUsual]

So where do I start looking to see if i have a gas problem?

Oh no....this too?... See doctor lol Sorry had to lol Cat and gas problem. You need some help. Good thing you posted here for us to help

 

[liers99]

Had to put a new battery in it so a couple days of driving and I should be able to get the code out of it.

 

[liers99]

Took a week of driving but the light came back on. The code I am getting is P0430. It's a catalyst code. I am also getting a bad gas smell especially after a long run down the interstate. It smells like burnt raw gas if that makes sense. What should I check?

 

[liers99]

Anybody?

 

[MAS Tequila]

Is it running smooth?

A non firing cylinder would send raw fuel through.

Rock Auto has about the best price on the cats.

I had a cat plug up on a mid 80's Firebird, and it stunk like raw fuel. But it wouldn't go more than 40 mph until the cat was pulled.

It may just be one of the cats.

MT

 

[liers99]

It doesn't seem to have a miss but when I watch the o2 sensor data while I'm driving it looks weird to me. Don't know what I am looking at exactly but it seems it should be more consistent. I just don't want to sink a bunch of money into new cats and exhaust just to have them fail again because I didn't fix the real problem. I don't know much about gas motors I usually play with old diesels so the help is much appreciated.

 

[fritz24]

Before you spend money on parts, I suggest you bring your car to a garage and let them check the compression of each cylinder and the fuel pressure with KOEO/ KOER. You have to determine why it is sending raw fuel to the exhaust and cause the cat to fail. If everything check out fine then its time to do the tune up. Clean the iac maf and throttle body while you're there.
Nway may i ask what is the value of your long term fuel trim on both banks(engine in operating temp)? If it has a negative value that is high(above -20%), rev the engine to 2000 or 2500 rpm for 10 sec and see if the fuel trim climb up close to zero or if the trim will even drop to higher negative value. Report back

 

[Turdle]

Try a new set of autolite platinum spark plugs. ignition misfires will not log a trouble code, but will cause an unburned fuel symptom.

No other brand of spark plug will work well.

 

[liers99]

Fritz24 do I need to check it while driving down with load on it or just sitting in the drive? What would be considered normal?

 

[fritz24]

Any, as long as the engine is running and warmed up.

 

[liers99]

Ok I'll check it out.