2005 T&C 3.8. 129k miles. Several months ago, I got a P0420, Cat Conv efficiency below threshold. Over the past couple of months, it has gradually lost power, to the place that it now falls on its face if you give it WOT (won't rev past about 4k). Between the code, the loss of power, and the fact that it's an oil burner, I'm thinking the cat is plugged. Sound like a reasonable diagnosis?
catalytic converter
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Originally Posted By: zrxkawboy
2005 T&C 3.8. 129k miles. Several months ago, I got a P0420, Cat Conv efficiency below threshold. Over the past couple of months, it has gradually lost power, to the place that it now falls on its face if you give it WOT (won't rev past about 4k). Between the code, the loss of power, and the fact that it's an oil burner, I'm thinking the cat is plugged. Sound like a reasonable diagnosis?
I think you're on the right track. I'm helping a friend with an 08 Expedition with a P0420 code. We cleared it, a day later it came back with a cam position sensor, bank 2, and no P0420. We swapped that out cleared the codes again, and P0420 came back. He wants to change the plugs and coil packs since the truck has 102K miles on it. I told him that was a good idea but it isn't going to solve the P0420 code. He tows a 4,000 lb trailer 5 days a week with it, and it is starting to lose power and ping. The 02 sensors are worth a shot but I think he's looking at a new CC, and so are you. He was driving around with a CEL for a few months now, and I have a feeling he might have had a miss and killed the CC, but I didn't see a code for a miss.
2005 T&C 3.8. 129k miles. Several months ago, I got a P0420, Cat Conv efficiency below threshold. Over the past couple of months, it has gradually lost power, to the place that it now falls on its face if you give it WOT (won't rev past about 4k). Between the code, the loss of power, and the fact that it's an oil burner, I'm thinking the cat is plugged. Sound like a reasonable diagnosis?
I think you're on the right track. I'm helping a friend with an 08 Expedition with a P0420 code. We cleared it, a day later it came back with a cam position sensor, bank 2, and no P0420. We swapped that out cleared the codes again, and P0420 came back. He wants to change the plugs and coil packs since the truck has 102K miles on it. I told him that was a good idea but it isn't going to solve the P0420 code. He tows a 4,000 lb trailer 5 days a week with it, and it is starting to lose power and ping. The 02 sensors are worth a shot but I think he's looking at a new CC, and so are you. He was driving around with a CEL for a few months now, and I have a feeling he might have had a miss and killed the CC, but I didn't see a code for a miss.
One more test you can do is use a vacuum gauge to check for any restrictions in the exhaust system. If vacuum drops when holding the gas around 2,500RPM that means you have backpressure building up from a clog in the exhaust system (cats, bad muffler, etc.)
The fact that it's an oil burner would also lead to a clogged cat. I'd resolve the oil burning issues first.
The fact that it's an oil burner would also lead to a clogged cat. I'd resolve the oil burning issues first.
Replace the oxygen sensors along with the cat.
Walker and Eastern make good cats.
Walker and Eastern make good cats.
Yep sounds just like a clogged cat.
With a clogged Cat you will have excessive heat in the exhaust manifold between the engine and the Catalytic Converter. It's fairly easy to pop the hood and check. it will be obvious. Don't burn yourself.
Mine petered out at 200,000 miles on my Hyundai Accent.Got the codes,fixed them and 2weeks later my top speed was 4mph. Should have got a test pipe for it. Had Honda tow it in and they gave my 2000.00 sight unseen and I walked away without a care or another Korean car in my world. Kia Hyundai better than domestics but parts hard to fine AND expensive like a gold digging ex girlfriend. Coldest beer I had never came close to ex lol.
Pop out the upstream O2 sensor and give it a quick test run. It will make a [censored] of a noise, but you should pick up a little power. The burning oil has clogged the cat. Replace the cat and it will clog again. You need to address the oil burning issue, then the cat, upstream O2 sensor(s) and spark plugs should be replaced. It would hurt to do a top engine treatment, but at this stage it may too late for that to work. I can recommend Davico converters first hand as I just put one on my pickup. Fit perfect. Good luck.
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