Misfire after LT header install & tune update: HELP!

[PQ]

Never know, you may be benefiting from the headers, cat delete AND the fuse pull.

So here's to you having no more problems.........

[2010victoryred]

Originally Posted by fldrummer

That's a good assumption.

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Just an update... I was able to pick up the new front O2 sensor at NAPA today. After getting home from work, my neighbor was kind enough to lend me his jack & stands and I was able to swap out the bad sensor with the new one. I noticed (actually, my exhaust installer noticed first) that when you shake the old one (while holding the washer down), we could hear something rattling around inside; the new one would not do this, leading me to believe something internal was fouled up on the old one. I went ahead and also pulled the number 5 & 20 ECM fuses, as well as disconnected the battery for 20 minutes.

After reconnecting everything, I fired her up and let her idle (no CELs, so far) for a couple minutes before taking her for a quick spin down the road. Everything seems back to normal, so far, as the power was back, especially in the upper RPM range (I almost lost traction at 5K RPMs with the new-found power ), and then some. I think I lost some low-end grunt, unfortunately, with the lack of cats and the large 3-inch piping, so maybe I'll throw some HF-cats on down the road, after giving the computer time to re-learn my driving style...

HOWEVER, since I've only driven the car about 3 miles, so far, I have to throw caution to the wind about my optimism, as I didn't have drivability problems coming out of the shop for a few more miles/cycles before this issue presented itself. The real test will come tomorrow, as I'll have a 70-mile round-trip to make. If I get through tomorrow without more issues or CELs, THEN I will breathe easier. *knocks on wood*

Thank you all, once again, for your help & insight!

cool man glad you got everything sorted out

[fldrummer]

Originally Posted by 2010victoryred

even if that wasnt the issue you should definately change that sensor anyways you dont know for sure what the tech acually did to get that sensor out may being giving off some wrong readings i wouldnt even drive with that sensor in the car of course after you fix the misfire good luck man

'Took some pics (sorry for the poor quality & background; should have put them on the ground, like I did the plugs--2 unsteady hands this time; LOL) of the old sensor. As you might be able to see, the threads were pretty stripped, as were the contact points for the wrench...

[fldrummer]

Originally Posted by PQ

Never know, you may be benefiting from the headers, cat delete AND the fuse pull.

So here's to you having no more problems.........

I thought the fuse pull was mostly for the L99 guys though (?); I have a manual LS3. Either way, it obviously didn't hurt.

[2010victoryred]

yep i had 2 o2 sensors strip on me when doing my header install something ive never seen on a brand new car with 1000 miles but with my luck i would expect nothin less lol

[PQ]

Originally Posted by fldrummer

I thought the fuse pull was mostly for the L99 guys though (?); I have a manual LS3. Either way, it obviously didn't hurt.

Nope. Couldn't hurt. Lotta LS3'guys swear it helped them as well.

Originally Posted by 2010victoryred

yep i had 2 o2 sensors strip on me when doing my header install something ive never seen on a brand new car with 1000 miles but with my luck i would expect nothin less lol

When I swapped my headers one of mine was the same way. Literally had to get a pipe to get it out.

[fldrummer]

Well, I drove my 70-mile trip last night w/out any issues or CELs popping up, so I think this issue can be considered solved...

Now it's time to swap out my "weak" MAF for one of the good ones (next week). Anyone think I should pull the ECM fuses again when I do this or just plug & play? Also, does anyone know some good 200-cell HF cats for a 3-inch exhaust? The only ones I've seen are some Magnaflows, but they are 300-cell, if I recall (?).