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Discussion Starter #1
So a couple months ago I had mid length headers and catless H pipe installed on my car. I was still using Bama at the time and I was having problems with my o2 sensor on the right side. My check engine light would come on and off, but I didn't notice any issues with performance.
About a month later I took my car back to the same guy to have him install my 3.73 gears (stockers were in there) and have him perform a street tune to see what life without Bama was like. He also switched the o2 sensor from the right side to the left side because I was a cheapskate at the time(the light only came on once since indicating a problem on the left side now). The car drove great for 3-4 weeks, and then my aggravation began.
First, I was driving the car rather aggressively the other day in 4th gear and my car got to about 4500 RPMS and the car felt like it hit the rev limit. I shifted to 5th gear and same problem at about 5000 RPMS. Then a week or so later it happened in 3rd gear at about 4500 RPMS. Is this because of the 3.73's?? Now the more I drive the car, the stronger the exhaust smell is getting. The smell is obnoxious now. Smells like it is running rich. Finally 2 days ago my check engine light came on. I ran the code and it came back P0030 (Random misfire). I did change the coil on plugs and plugs a few months ago but I have never had a problem. Checked everything and it seems tight.
Not really sure where to begin? I guess I should call the guy that did the work. Anyone else have any of these problems with similar mods? I'm nervous I'll have a big repair bill. Any help/advice/ideas as to what it might be will be great.
 

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Usually with the Kooks headers o2 placement isn't a problem. Are you using extensions by any chance? Did you replace the 02 sensor?
 

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Yeah I have not had an issue with my kooks headers. No need for extenders the harness reaches fine.
 

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Discussion Starter #5
I re-used the stock o2 sensors. Yes there are extensions because the original wires were too short I was told.
 

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That's bs. They reach absolutely fine. Good call Scott.

Take the extensions out.
 

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Discussion Starter #7
So even the code with the random misfire could be caused by this damn o2 sensor?
 

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The problem is probably the use of the o2 extensions. Get them off ASAP. If you reach up to the top of the transmission there are several places to unhook the harness. That will allow you to release the harness and give you the appropriate length.
 

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To be honest with the kooks I didn't even have to unhook it from the bellhousing bolt with the harness clipped onto it. But if you need to then do it
 

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Yea I didn't even think about that Shaun. With my longtubes I had to but the design of the Kooks mid lengths should make things even easier.
 

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i was throwing o2 sensor codes left and right as well, i took off my extensions about 1,000 miles ago and no more codes.. and runs even stronger now..
 

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So even the code with the random misfire could be caused by this damn o2 sensor?
Yes O2s can cause misfires, it happened when I put long tubes with extensions on my 08 4.6. I'm assuming it causes the ECU to mismanage AFR causing a chain reaction type of even and could cause a cylinder to fire out of sequence. Might not be the most correct explanation but I know O2s can cause misfires
 
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