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Random misfire

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Old May 26, 2012 | 02:55 PM
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Default Random misfire

Tried this once before and got alot of views but no responses..

Car has had a hesitation/misfire problem for a while. (Before mods and now after) But it always comes and goes. Its there for like a a day then goes away and returns a couple of days or a week or so later. Really starting to irritate. Its at idle and under light load like cruising around town in low rpms. The service engine soon light actually started flashing at me for a little bit.

Car is showing random cyl misfire. Checked it on a scanner that can monitor individual cylinders. It shows misfires on all cylinders randomly.

Shows low voltage on bank 1 sensor 1. I have changed o2 before. Still there. Trying to figure out why. Could they be related?

2001 WS6 A4 127,xxx miles
Recently installed-
NGK plugs
Wires from ws6store.com
Removed air pump
Mac mid length headers
ORY
Circle D 3200 stall
Built 4l60e
Poly motor, trans and torque arm mounts
New knock sensors
Knock sensor wiring harness

Like I said, the problem was there before I installed any of this. And now its back again. Please help. This car is about to get molotov'd.. Had ENOUGH
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Old May 26, 2012 | 03:15 PM
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I forgot to mention it seems to only happen after I beat it a little bit. It started again today after I did a little sprint down a back road.
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Old May 26, 2012 | 05:14 PM
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P0135
P0300
p1133

Codes showing right now. The misfires went away after the car was driven normal for a while. I noticed that the misfire went away after valve train noise died down and an exhaust leak sealed itself. There is a noticable leak while its warming up. But once everything is nice and warm the pipes must expand enough to seal it. After sitting for a little while the pipe cool down enough to leak again. Thank you MAC.. Thats what I get for buying cheap used parts. I have to get a new y pipe made. Also, just throwing this in there, I was NOT beating the car while it was cold. Engine temps were around 200 and trans temp was around 150ish.
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Old Jul 7, 2012 | 05:24 AM
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I'm having the same issue bro but my misfire is constant and no hesitation which I find odd, of what i've read if you have a bad misfire it can throw a code, not completely sure though, I would recommend going a compression test if you don't know how to do this lots of good videos on YouTube how to do this etc the car guy explains it well in my opinion. Make sure you have no vacuum leaks as this could be lead to some of the issues . On the compression I found that 180 is normal for or years test your wiring from the harness on the o2 to make sure its getting 5v from the pcm . miserly though its coming to do with compression, if you get 2 cylinders side by side that are showing about 160 then its prob a head gasket .oh is there any oil on the plugs? Any further Queston feel free to pm me
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