Lt1Porsche

iTrader: (6)

To start off I went on vacation and when I came back my mom had driven my car to and from work. When she got home around 4:30 the family had dinner and then around 6:45 I decide to go on home. Car started normal, started to drive up the road. Got about 3/4 mile away and the car started to miss horribly. I turn around drove back to my dad's. Right before I got to his driveway the issue stopped. We checked a few things out and blamed the heavy rain for the issue. I drove it to my shop and hook up the scanner. I pulled a O2 Sensor code for b1s1 and a p0300 random misfire. This was Sunday. Thrusday heading home from work I got on her a small bit. Just a quick 1st gear pull, when I got to the stop sign the same issue started to happen again. Drove for about 3/4 mile and it cleared up. Friday morning heading to work. Start up it drove fine. Drove about 3/4 mile and she started cutting out bad. 1 mile later it stopped. Got to work. Hooked up the scanner and checked the codes. Random misfire and b1s1 low voltage. Let it sit for a bit and pulled it in. Checked the b1s1 voltage and it was around 80 mv. Replaced the sensor and that went up to 450mv - 460mv. Problem still there. Replaced the spark plugs with new TR55's because the ones that were in there are about 25K old. Cleaned the throttle body and IAC. Descreened the MAF. Replaced my PCV hose because it was cracked. Problem still there. Ran a few more test to find that when first switching from open to closed loop and under load the coil packs would randomly die off. And being that this was occuring on all cylinders I declared it was not the coil packs themselves. So I removed the ECM and had a buddy at NAPA reflash it back to stock (it has never been tuned or tampered with before) The problem no longer occurs. My question is what would have caused this in the first place? My friend said there were multiple KS codes and other codes. Im not tuned but have removed the AIR and EGR have LT's, no cats, no rear 02's, LID and K&N filter, descreened MAF, and TSP Rumbler X. So what are some of your expert opinions.

Lt1Porsche

iTrader: (6)

Anyone got an idea at all?

redsscamaroboy

iTrader: (7)

I have had the same type running problems with my 00 SS A4.
First happened on a trip to Texas,(long way from home) and i found the O2 sensor on the driver's side was reading about 80 mv,way lean!
At that time i replaced (Both) o2's with new Delco sensors only to find still the same problem. The condition kinda stopped for a long while,then i would notice at start up the car would fire up kinda funny,started everytime,just sometimes it sounded like it was firing only on half the motor for the first 1-2 seconds. NO codes and no other leads.

I did finally find that the wire harness connector for my driver's side coil had a corroded and (green) terminal in it. I cleaned it and applied some die electric grease to the connector. Seems to be better.

Double check your coil harness,it is free and easy to check.
Good luck

Dave

Lt1Porsche

iTrader: (6)

bump....

Slvr00Bird

iTrader: (2)

Get a set of headers and a tune!!! LOL

Viper

iTrader: (6)

Can you swap your MAF with a buddy? Or run SD for a bit and see if the problem happens there.

YellowToy/A

iTrader: (1)

I will bet this was a bad connection with the ECU and the harness. When you removed the harness and replaced it that was the was fix. Iwould take off the harness and look at all the connector and make sure they look good. Also get a tune or find a stock MAF. Not sure if you are rich or lean but lean is bad and rich uses gas.

Lt1Porsche

iTrader: (6)

When I pulled my plugs the drivers side of the motor was running rich and the passenger was a little bit lean but not bad at all. I really need to get a tune. But does anyone else have any ideas.

TAQuickness

iTrader: (28)

Another thing that may have been happening - when your B1S1 O2 started going out, it likely caused your fuel trims to be way off. Old plugs and a rich condition could cause some of the problem you were having.

+1 on YellowToy/A's comment.

RRing the PCM would cure a loose/slightly corroded connection and the reflash would reset your trims.

All this is just guessing though.

Lt1Porsche

iTrader: (6)

I thought about that but I clear all codes and replaced the plugs and the bad O2. Then took it for a test drive and it still did it. When the car was power-braked the coil packs would drop off one at a time.