[bassboi]

2006 Base Coupe, 43K miles, JWT TT with Air/Fuel Ratio and Vac/Boost gauges, 2.5" Stillen Cat back exhaust. Second owner (bought '08).

The original owner had the turbos/exhaust installed when he bought the car, then wrecked it at 15K miles. I bought it in Long Beach, CA with a Rebuilt title, had it checked out in San Diego by a Z specialist and drove it to FL in 52 hours uneventfully. Over the years I've sorted a few minor problems and rarely engaged the turbos.

In a normal situation with an up to temperature engine the AFR gauge reacts to engine load/RPM. Now on cold or warm startup the AFR goes full rich, to full lean for a second or two, back to full rich and stays there, independent of engine temp and RPM. Car seems to run smoother as it warms but still with a random miss.

I'm considering changing the plugs/coils and MAF. Seems like routine maintenance at this point. Anything else I should be looking at? Thanks!

 

[dkmura]

Since I don't own a FI Z33, I've waited for somebody else to respond. Not seeing any takers, I'll throw in my $0.02. Any modified VQ35DE with a modded or standalone ECM has parameters carefully honed on the dyno. Can you take it to a local Nissan tuning or specialist shop to have them check the tune? Before you start swapping out parts that may be perfectly adequate for the job, get a second opinion first...

 

[bassboi]

Unfortunately the nearest Z specialist is in Orlando, around 200 miles away. Z1 is in Atlanta, 350 miles. My experienced mechanic retired last year. I'm going to give CRC's MAF cleaner a shot tomorrow and will report the results.

 

[macanic308]

2006 Base Coupe, 43K miles, JWT TT with Air/Fuel Ratio and Vac/Boost gauges, 2.5" Stillen Cat back exhaust. Second owner (bought '08).

The original owner had the turbos/exhaust installed when he bought the car, then wrecked it at 15K miles. I bought it in Long Beach, CA with a Rebuilt title, had it checked out in San Diego by a Z specialist and drove it to FL in 52 hours uneventfully. Over the years I've sorted a few minor problems and rarely engaged the turbos.

In a normal situation with an up to temperature engine the AFR gauge reacts to engine load/RPM. Now on cold or warm startup the AFR goes full rich, to full lean for a second or two, back to full rich and stays there, independent of engine temp and RPM. Car seems to run smoother as it warms but still with a random miss.

I'm considering changing the plugs/coils and MAF. Seems like routine maintenance at this point. Anything else I should be looking at? Thanks!

Sounds like an MAF sensor. Have you had a good diagnostic scan ran? Tune up?

I use this scanner if you are inclined to use one.

 

[bassboi]

Sounds like an MAF sensor. Have you had a good diagnostic scan ran? Tune up?

I use this scanner if you are inclined to use one. View attachment 53416

CRC MAF cleaner worked! AFR settles down within 5 minutes of startup and functions normally. The miss disappeared, idle is smooth and the car pulls well. Put 100+ miles on it today from 25 to 80 MPH. Computer estimates its usual 29-30 MPG at a steady 65 mph.
I have a BlueDriver scan tool, pretty basic. Thanks for the Autel link, I'm more inclined to pay someone for a complete scan after I replace the original plugs.