ZR8ED

I'm now chasing a slight miss/popping from the exhaust, and idle that is irregularly hunting by about 50-100rpm.

86 n/a with a Rogue n/a tune.
I've been running the n/a tune for a couple of months now with no issues, and it was running quite well with lots of power.

Fast forward to our recent cold weather spell. My tps fails, and while troubleshooting, I find that #1 exhaust is running 200 degree hotter than the rest. When listening to the injectors 3 made a nice "tic tic tic" sound with cyl #1 injector making a bit of a "thunk thunk thunk" sound. We find the fuel filter clogged up and dirty, so after changing the filter/screen front and back, I send the injectors out to be cleaned. All is well except now when I set the idle, I can here a bit too much "burbbling" from the exhaust, and the idle is now iregularly hunting about 50-100rpm.

In the last week I have:
Replaced the plugs, wires, cap rotor, fuel filter, speed/reference sensors, tps all with bosch equipment. I even swapped back to a stock dme and afm. (before the I discovered the injector issues) no change.
Can't find any vacuum leaks.
BUTTTT I did notice that when at WOT getting on an onramp, I can smell that rotten egg smell from the cat (cat is 1 yr old)

What do you think the odds are that the car is now running a bit rich now that the injectors are cleaned and maybe flowing more fuel than before? The smelly exhaust is making me think this. I'm now considering pulling the dme and try to dial out some fuel.
Suggestions? The car is my daily driver 1000km/week and I am working on it as well as a local Porsche mechanic, but he is not familiar with the maf kit at all.

Paulyy

o2 sensor?

konakat

Is the exhaust temperature discrepancy fixed? If one cylinder is running rich, that is a much different debug path than all of them running rich. If the discrepancy is fixed, I agree with O2 sensor being a likely culprit.

ZR8ED

Sorry forgot that. Exhaust temps are all even across the cyl. The injectors all sound the same. I checked myself afterwards to check the sound.

O2...now you got me thinking again... I won't be replacing it right away even if it is not working right, as it would take a while to get one in. I'll pull one of my new plugs and see how they look after a week in the car.

As a side note, the car does feel pretty fast..even a bit faster than before according to my buttdyno. I love the n/a tune btw.

konakat

I'm not sure how sensitive these cars are, but incorrect spark gaps could also cause unburnt fuel to make it into the exhaust.

ZR8ED

Might as well check that while its out. .028 - .031 gap in case anyone is interested. As an FYI for others reading. Yes. Spark gap does make a difference. Always check new plugs, even if they say "pre gapped" If they have traveled and bounced around during shipping, they may no longer be gapped correctly.

That I can check quickly tonight.

william_b_noble

for O2 sensor, use the Bosch universal replacement, about 1/10th the price

fred27

You might want to check that the diaphragm of your fuel pressure regulator has not failed. I had the popping from the exhaust and found fuel spilling from the regulator when I pulled the vacuum hose from it.

ZR8ED

Update. I pulled one plug and checked the gap. Less than 20 thou...I checked them all and found none more than 23 thou. I reset them all to 31 thou. It runs much better now. I will monitor and see if that solves it. It is super cold out, so I'm not going to be pushing it all that hard to test WOT.

use2windsurf

I had similar issues and did much of what you have done. The two things that I did that seemed to finally solve the problem was to do a throttle body reseal with the Arnnworx kit ($20) and replace the O2 sensor. Every o ring in the TB was shot. it now idles at steady 800 RPM once warm and I couldnt get it to idle below 1000 before.