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- February 2, 2002
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- Year, Model & Trim Level
- 1998 Mountaineer AWD
All it technically means is that it’s leaking. You’ll have to pull it to see why.
So I just went out and pulled the upstream O2 sensor...took it for a drive. It was loud but it has more power than it's ever hadAll it technically means is that it’s leaking. You’ll have to pull it to see why.
if you have an air leak near that sensor it will read incorrectly from all the outside oxygen being sucked inUpdate... The air leak I heard is actually coming from the o2 sensor in the cat. Does this mean the cat is clogged? Or if it's a rust hole would it make my truck run like crap?
I ended up removing the upstream O2 sensor. The truck has full power with it out. I'm thinking the cat is clogged?Were you able to snug it back down and stop the leak? Did you try cleaning the sensor with electronics cleaner?
could be the cat, but have you verified its not the o2s and the exhaust leak checks out?I ended up removing the upstream O2 sensor. The truck has full power with it out. I'm thinking the cat is clogged?
Maybe but cats aint cheap. I take that there was not a rust hole? Just wondering what would happen if you cleaned the o2 sensor and replaced it. Does it still sound like it's leaking when the sensor is replaced?I ended up removing the upstream O2 sensor. The truck has full power with it out. I'm thinking the cat is clogged?
The leak is like a hiss. Like it's coming out a small hole. I'm buying new o2 sensors tomorrow. I'm gonna try them before I make my move on the cats. I did try unplugging them first but it didn't change anything until I took it outcould be the cat, but have you verified its not the o2s and the exhaust leak checks out?
Yes it's coming out. Hissing like a small hole. I took the o2 sensor out because I seen it on another post...said it was a good way to test the cats so when I did it I was shocked. Besides the loudness it was like a brand new truck. I'm almost certain now that it's the catIf it was loud then that means that you removed it completely and ran it leaving a hole before the cat. I wouldn't think that size hole would improve things that much with a clogged cat but it appears that it did. If it was the sensor - then logic would say if it's flopping in the wind now and it's running better then it's getting more clean air than it ever did before so how would a leak around it supplying fresh air to it screw things up more than it being physically out of the exhaust stream?
Sounds like the air leak was air coming out - not being sucked in.
It ran better without the sensor in the hole. Find another way to plug the sensor hole and if it still runs bad then it's the cat.Yes it's coming out. Hissing like a small hole. I took the o2 sensor out because I seen it on another post...said it was a good way to test the cats so when I did it I was shocked. Besides the loudness it was like a brand new truck. I'm almost certain now that it's the cat
Timing chain guides?I'm wonder how I should approach this. I've done the plugs and wires, fuel filter, tried to find a vacuum leak with no success. Is it a bad cat? MAP- EGR valve? O2 sensor? I've got a loss of power, feels like something holding it back and it has a rough idle but not all the time. This morning when it was cold it didn't want to go at all chugged real bad took me about a mile to get up to 60. Motor has around 95 k the truck has 250k. Any help would be greatly appreciated thx
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Have you traced out the harnesses? Some models have an issue with brittle wiring insulation that have caused a host of problems.
If it’s not a wiring issue, I’d suspect you’re getting too much fuel. If you clear the codes does the cylinder 1 misfire come right back?
Have you traced out the harnesses? Some models have an issue with brittle wiring insulation that have caused a host of problems.
If it’s not a wiring issue, I’d suspect you’re getting too much fuel. If you clear the codes does the cylinder 1 misfire come right back?
Hey our Vin numbers are one digit apart, I have the exact same car, with exact same problems. I had to change my heater hose vac due to the fact that it lost all the fluids because the little plastic pos broke. Still having surge issues, rough idle. I'm gonna try a wiring harness next. Change out all the hoses. Get a new mass air flow sensor and connector. Then probably check out the oem. I am not a mechanic but, I'm following this guy chrisfix on YouTube and step-by-step going through each thing until I get to the bottom of it. He's good! Check EGR valve. Bad alternator could be the culprit , too. At 200+ miles, these things just go.I'm wonder how I should approach this. I've done the plugs and wires, fuel filter, tried to find a vacuum leak with no success. Is it a bad cat? MAP- EGR valve? O2 sensor? I've got a loss of power, feels like something holding it back and it has a rough idle but not all the time. This morning when it was cold it didn't want to go at all chugged real bad took me about a mile to get up to 60. Motor has around 95 k the truck has 250k. Any help would be greatly appreciated thx
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Thx for the help everyone. I'll post my results as soon as I fix it