rough idle/lack of power

[luvmyexpedition]

I have an 01 Expedition, and I have been having a problem with the idle and it is getting worse. Sometimes the idle speed slows way down and I can actually hear it knocking. When I drive, it lacks power, and I often have to turn off the overdrive in order to keep the rpm's high enough. When I first start it, it is usually not so bad, but as it warms up it gets worse. I took it to advance, and they put the scan tool on it and said I need an EGR valve and an O2 sensor, but a friend at work said his chevy did the exact same thing and he replaced the EGR valve and the O2 sensor twice, and the problem still did not go away, and it turned out to be his catalytic converter. So I was gonna replace those, but the Haynes manual doesn't say a lot about it, so I started searching online and saw all these people talking about having to cut the exhaust system off with a torch in order to work on it. I have surprised myself many times over the years when working on my vehicles, but that is definitely beyond my abilities. This is my only transportation and I cannot afford to get under there and make my car undriveable for any amount of time. Any advice about what the problem really is and how to fix it? Does replacing the cats really involve welding?

 

[Racenut]

Yes replacing the cats does involve welding and there are 4 of them. The low idle problem sounds like another alot of people have experienced with the PCV valve and line, the rubber "elbows" will actually rot and colapse on them selves or give you a really bad vacumm leak causing this. Search the forum there are many threads on this situation.

 

[luvmyexpedition]

Thank you, Racenut, so much for some very useful info. I went back to the Haynes manual for info about how to check the PCV valve, and then went out to check it. While checking it, I ran my finger up the vacuum hose and found a hole the size of my fingertip! It doesn't make sense, because there was really good vacuum at the end of the hose as well as through the valve. I may have created the hole myself; the rubber was actually very soft, as if melted. It makes me wonder if gasoline is somehow getting in there. Anyway, Auto Zone didn't have the part, so I bought gorilla tape, cut the bad part out of the middle of the tube, turned the pieces around so that the good ends were in the middle, wrapped it with gorilla tape and put it back on until I can get a new piece. It is not running 100%, but it is a thousand times better than it was. Mainly the problem now is the acceleration is "choppy" and it runs rough at 55, still rough at 60 but less so, and fine by the time I hit 62. Again, thanks a lot. You saved me a lot of time, trouble and money, you're awesome dude!

 

[Racenut]

Glad I could help. If you have any other questions throw 'em out there.

 

[mic_1011]

that elbow piece is notorious for going bad so don't blame your innocent finger. i had the same problem where somehow mine would just blow off. so i taped it tight and it's a;; good now.