Asmodeus

Does what sounds like a miss, a backfire, and stumbling/surging under 2000 sound like O2's? If I keep it over 2000 by slipping the clutch or keeping it in a lower gear than normal, it's fine. Wires? Coil? I don't have a Scan, and m afraid to drive the car too far.

I recently did a header/ory install. I changed plugs to denso iridiums. Car ran very strong for a while. Now, I have driven the car a couple hundred miles before my problem started (and my y-pipe never banged once). I did reuse the original O2's which now have 89,000 on them. There was NO hard driving over (5000 rpm) or missed shifts within 100 miles of this happening, I know this isn't mechanical.

HELP!!

thunder550

iTrader: (70)

My dad's stock 02 Tahoe developed a nasty idle shake, threw the SES light, but would smooth out after he got going. Turned out to be a bad injector. I have 122,000 miles on my original O2 sensors and they are working fine, so I would think yours would be too......but who knows, I guess they could be defective. Do you have an SES light?

stangkiller

i am gonna take a stab at this and say that it is o2's i had the same problem with mine. what you should do is go to advanced auto or some place like that and get it diagnosed. it it reads as a front o2 unplug it and take a quick trip down the road and see how it runs. thats what i did and my car drove fine after the o2 was unplugged. if thats your case then you know what your culprit is.

2001NBMZ28

Get it scanned, it's OK to drive as long as the SES isn't flashing.

GET_SOM

i second that.. after my header install I had the exact same problem plus one more lol... My car surged and stumbled, and wouldnt idle right at all. I took my car to autozone and borrowed their obdII reader.. it showed a misfire in my 7th cyl, along with my o2 sensors..

I guess somewhere along the line I mixed up my coil packs and put them on in the wrong order (i was under the impression that they were interchangeable; but after i changed em she ran fine) but that solved the misfire. As for the o2 sensors i just replaced them with my rear ones and I was back to running fine again. After a header install a lot of guy's o2's get fouled out.. so get it scanned and start from there.

stangkiller

you replaced your fouled out front one with your rear ones?

GET_SOM

yes, i bought o2 sims when I took the rear ones off.. so they were just laying around in my garage. When I saw that my front two fouled out I just threw in the ones from the rear and everything was good to go.

stangkiller

damn then thats what i need to do too. cause my passenger side fouled out and i didnt want to spend big money on the vette 02s and my rears are sitting around too.

Asmodeus

I have had the SES light on ever since the swap since I did not put sims in for the rear O2's, and removed my AIR and EGR. I was going to wait til I finshed my bolt ons (LS6 intake, possibly ported TB) to go get it tuned and codes cleared. Will not having cleared previous codes be a problem? It NEVER threw an SES prior to this.

stangkiller

not it wont be a problem it will just print out a list of all the codes you are throwing. just go to advanced and get it scanned for free, of course its gonna throw the rear o2 codes as well as the egr and the air, but you will know what your problem is if it throws the the codes for the front. i took mine in with the air off and everything and the guy scanned it and said that i had a whole huge list of stuff to fix.

Asmodeus

ok, nice

So, what else besides O2's COULD it end up being? Just getting ready to break the news to the bank account if it's major.

stangkiller

it could be the wires aint on the plugs all the way or touching the headers, or the plugs not all the way in the head or possibly cracked

Asmodeus

UPDATE:

I just came inside from under the hood. #6 plug was loose to the touch, #8 wire was barely hanging on to the end of the plug by the shield spring. Tightened #6, replugged #8, she purrs like a tiger again. I did make sure to check all the others too. Guess the guy who put my headers on didn't do quite as good a job with the plugs and wires.

stangkiller

glad to hear that you got it all sorted out.

emerica4601

iTrader: (5)

same thing happened for me.
another vote for primary o2 sensors. one of them is not connected. for the misfire, one of your plug wires is probobly touching your header and melting it to the core wire.

all this will cause the hesitation, surging, and whatnot

LeddySS98

I put new wires on.... MSD's replaced my Taylors... and my popping backfire stopped.. the stutter under 2k gone....

all it was were the wires... one of the taylors had backed off of the back plug on the passenger side, and 2 of them were corroding...

New MSD wires, and the car came alive.