3.0 running rough all of a sudden....

[Mikelb01]

Driving home last night, my car seemed to all of a sudden run like crap. It had basically no power and would barely idle. I did an Auto-scan via Vagcom. Here is what I came up with:



Got any ideas? I figured it was a coil pack issue and I plan on replacing all of them tomorrow.

[SJorge3442]

Ahhh. The 4,5,6 misfire issue. I've been battling this for A LONG time (actually only like 2k miles, but thats a long time for me). I swapped fuel pump, coil packs, but I would still end up getting the 4,5,6. Mind you, I was running a kompresd tune which has since been deleted off the ECU(overwritten with Zimbu's tune) so it can cause no harm to anyone else. Im 99% sure this tune caused me to blow a set of stock coils, as well as a few R8 coils. I'm not sure whats up with it, but before tune I had no misfire issues, and after the tune its been nothing but misfire issues.

Anyway.....

One night my car FINALLY threw a code for the front o2 sensor on the drivers side (bank with cylinders 4,5,6). I swapped it out with an NTK sensor from amazon and BAM! No issues and the misfiring went away. I'm not sure what took so long for the sensor to throw a code, but when it finally i did I sat there thinking "Yup, that makes perfect sense". I'm not saying thats 100% your issue, but if the coils don't fix it, it's probably time for a new o2 sensor. I plan on doing the passenger side soon just so they are both up to date with the same mileage.

[Mikelb01]

My car has been throwing the P0431 code. I cleared the code this yesterday morning and then started running like crap yesterday evening. Would the P0431 more than likely refer to the O2 sensor?

[SJorge3442]

My car has been throwing the P0431 code. I cleared the code this yesterday morning and then started running like crap yesterday evening. Would the P0431 more than likely refer to the O2 sensor?

Thats for the rear o2 sensor. That sensor does nothing but measure the efficiency of the catalytic converter. It's reading DO NOT adjust any engine PIDs. Pretty much every 3.0 has those codes, unless you put new sensors/cats/o2 sensor spacers in. It took a long time of my car running rough before the front o2 sensor code was tripped. I believe that code was a P0150.

[Mikelb01]

Welp, I replace all of the coil packs tonight and the car still won't start. I didn't have very long to work on it. Any ideas on what I can look at tomorrow when I have more time? Any help is appreciated! After my problems the other day, it won't even turn over. Worst part about it is the car is stuck at my Exes house!

[SJorge3442]

Didn't know you had a no start condition. Time to narrow it down. Likely a spark or fuel issue. Clogged fuel filter maybe? Is the fuel pump priming when you turn the key? You can usually here it hum the first time you turn the key to the on position

Sent from my Nexus 6 using Tapatalk

[Mikelb01]

I'll have to listen to it tomorrow when I go back to work on it, but I don't recall hearing it pressurize. If the fuel pump goes out does it make a buzzing/hissing noise? I thought I heard something the other day when it started having trouble, but couldn't really tell because of a neighbor playing his radio too loud. My car has 175k on it. Since I've owned it (145-175k), I've replaced the fuel filter once. Is there a schrader valve on the end of the fuel rail on the 3.0's? Not sure if the fuel pump has ever been replaced? Also, I haven't done the timing belt yet.

[19jdog]

No start? I say check fuel pump, fuel pump fuse, and fuel filter. You could also unhook the fuel rail crank the car and see if it squirts all over the place.
How old are the coil packs? I doubt they all went at the same time thou...

[SJorge3442]

I'll have to listen to it tomorrow when I go back to work on it, but I don't recall hearing it pressurize. If the fuel pump goes out does it make a buzzing/hissing noise? I thought I heard something the other day when it started having trouble, but couldn't really tell because of a neighbor playing his radio too loud. My car has 175k on it. Since I've owned it (145-175k), I've replaced the fuel filter once. Is there a schrader valve on the end of the fuel rail on the 3.0's?

No valve on the rail. There's an inline fuel gauge you need to add into the line right before the soft line turns into the hard line.

The pump will groan when its dying. Usually it's a quick half second hum when working properly

Sent from my Nexus 6 using Tapatalk

[Mikelb01]

If my fuel pump did shit the bed, would it cause my car to misfire/run rough as crap with virtually no power and possibly not even run?

- - - Updated - - -

If my fuel pump did shit the bed, would it cause my car to misfire/run rough as crap with virtually no power and possibly not even run? Forgive my ignorance.

[imnuts]

Yes.

[ZimbutheMonkey]

Ahhh. The 4,5,6 misfire issue. I've been battling this for A LONG time (actually only like 2k miles, but thats a long time for me). I swapped fuel pump, coil packs, but I would still end up getting the 4,5,6. Mind you, I was running a kompresd tune which has since been deleted off the ECU(overwritten with Zimbu's tune) so it can cause no harm to anyone else. Im 99% sure this tune caused me to blow a set of stock coils, as well as a few R8 coils. I'm not sure whats up with it, but before tune I had no misfire issues, and after the tune its been nothing but misfire issues.

Anyway.....

One night my car FINALLY threw a code for the front o2 sensor on the drivers side (bank with cylinders 4,5,6). I swapped it out with an NTK sensor from amazon and BAM! No issues and the misfiring went away. I'm not sure what took so long for the sensor to throw a code, but when it finally i did I sat there thinking "Yup, that makes perfect sense". I'm not saying thats 100% your issue, but if the coils don't fix it, it's probably time for a new o2 sensor. I plan on doing the passenger side soon just so they are both up to date with the same mileage.

Hey long time no speak, I didn't know that you actually flashed my file to your car, how did it work? (good I hope )