Misfires on one cylinder bank (CYL 1, 2 & 3) on 3.0 V6

[NyteEscape]

So I've been running into an issue where I get random misfires on only cylinders 1, 2 and 3 while revving through the engine. The misfires only start above 6k RPMs, right at the top of the range. I can reproduce it every single time. I've tried swapping around plugs and coil packs, no luck.

I didn't do the timing belt myself, is there any chance the notch might be off on that bank? If so, how would I go about checking that? I don't have too much experience working on the 3.0, so kind of getting acquainted to it all. Also, I can't seem to get above 19mpg on the 3.0. This includes babying it to squeeze as much as possible out, still only getting 19mpg. Could this be related to the timing being off?

The codes I get are P0300, P0301, P0302 and P0303. Also getting a P0431, but not sure if that's related or not.

[MrTurrtle]

so you swap coils to cylinders that are not misfiring and clearing the faults after and they still come back for cylinders 1, 2, and 3?

[Blockis]

Yeah, are you clearing the codes after you swap them? I find this awfully interesting actually.

P0431: Warm Up Catalyst; Bank 2: Efficiency Below Threshold - don't think it's related.

[RENOxDECEPTION]

So I've been running into an issue where I get random misfires on only cylinders 1, 2 and 3 while revving through the engine. The misfires only start above 6k RPMs, right at the top of the range. I can reproduce it every single time. I've tried swapping around plugs and coil packs, no luck.

I didn't do the timing belt myself, is there any chance the notch might be off on that bank? If so, how would I go about checking that? I don't have too much experience working on the 3.0, so kind of getting acquainted to it all. Also, I can't seem to get above 19mpg on the 3.0. This includes babying it to squeeze as much as possible out, still only getting 19mpg. Could this be related to the timing being off?

The codes I get are P0300, P0301, P0302 and P0303. Also getting a P0431, but not sure if that's related or not.

Cylinders 1 2 and 3 are not on only one bank if I'm not mistaken.

[NyteEscape]

so you swap coils to cylinders that are not misfiring and clearing the faults after and they still come back for cylinders 1, 2, and 3?

Yup, swapped the coils and plugs around, misfires are staying on 1, 2 and 3.

Yeah, are you clearing the codes after you swap them? I find this awfully interesting actually.

P0431: Warm Up Catalyst; Bank 2: Efficiency Below Threshold - don't think it's related.

Yup, cleared the codes after the swap.

Cylinders 1 2 and 3 are not on only one bank if I'm not mistaken.

Maybe I'm mistaken then. I thought the layout was:

---FIREWALL ---
(3)---(6)
(2)---(5)
(1)---(4)
--- RADIATOR ---

If that's not the correct order, I'm even more confused as to why it's consistently 1, 2 and 3 if they're not even on the same bank.

[NyteEscape]

so some late night googling has led me to bent valves (http://www.audiforums.com/forum/audi...firing-132820/). Not sure of the relevance, but not looking forward to finding out if that's the actual issue.

[MrTurrtle]

if they are on the same bank, i would check the cam adjuster. could not be adjusting, not getting enough oil, stuck, watever. each bank has its own adjuster on a v6.

[RENOxDECEPTION]

Guess I was wrong

[sa_seahawker]

if they are on the same bank, i would check the cam adjuster. could not be adjusting, not getting enough oil, stuck, watever. each bank has its own adjuster on a v6.

Before going through all that, I would first check the coil harness for broken/shorting wires. I know on the 1.8ts that is an occur acne more frequent than some may assume.

[imnuts]

Check the harness first for any bad wires. After that, my guess would be bad cams, and then it would be timing/valves for option 3. Option 1 of checking the wires would be the easiest method, and probably the cheapest to fix. After that, it just goes downhill. You're correct that 1-3 are on the passenger side and 4-6 are on the driver's side as well for the cylinder order.