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Discussion Starter #1
What's up, was wondering if anybody had any idea on what could be causing the problem on my daily 2000 3.8 auto with180k miles.. Bought the car a month ago $600 running only thing wrong is the exhaust is broken off where it bolts to the exhaust manifold on both sides and that it shakes pretty bad. I changed the oil, oil filter, spark plugs, spark plug wires, motor mounts, transmission mount, MAF sensor, and exchanged the iac from my 02 3.8 to clear that as a problem. The shaking has gotten better but still there. It's very bad on cold starts but eases up when operating temp. When I rev it almost completely goes away. When I put it in gear it also eases up but is still there and still vibrates while being driven. I'm getting the 02 sensor codes like I expected but occasionally. It has thrown other codes but they will go away, don't remember the exact codes but I do remember that it had something to do with running lean. It will sometimes have idle problems after it has been driven for a hour or so. I've deleted the egr and have thrown a couple codes for it which go away but my buddy's egr deleted 99 3.8 has no problems after deleting the egr.. ran my 02 with open exhaust manifolds for a couple months with no problems at all. So why could it be effecting this car so much and what could be making it shake so bad but not as bad as when it's cold? Appreciate the help. I've been digging into this for a couple weeks now.


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It is likely that the large exhaust leak is causing the O2 sensors to misread the amount of unburned oxygen in the exhaust. The computer is receiving this faulty information, and is not able to properly adjust the fuel mixture.
 

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Discussion Starter #3
Is there any way I could turn the 02 sensors off until I get the exhaust fixed? My 02 ran open headers for months with no where near as many problems.
 

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No.
The engine needs the information from the O2 sensor(s) that is nearest to the engine to run properly. Without that information, the computer cannot adjust the air/fuel ratio correctly.
The difference between running an open exhaust and the exhaust leak that you currently have is the exhaust leak is leaking out BEFORE the exhaust has a chance to pass by the oxygen sensor, whereas all of the exhaust will pass by the O2 before exiting out of an open exhaust system.
 
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