So one day the car's running perfect, shifting instantly at WOT like it should with the transgo. The next day, I unplug the battery and swap out my polished intake for my 350z air box like I've done many times in the past, and don't drive the car for the remainder of the day.

The day after that, I take out the car and notice a delay in shifts under semi-aggressive driving. I test it out some more and the lag during shifts is still there, it's just like how it was when the car was stock, sluggish shifts. Car shifts the same way today as well.

Any ideas what could be wrong?

 

Weird, but I've got nothing for you, sorry. In for an answer though.

 

I don't know if this is technically correct but I've experienced similar results after unplugging or killing the battery. I believe it's just the trans computer resetting itself. After a few times driving it it should readjust to the transgo. I just killed my batter a few days ago and when i drove the car for the first time it seemed more sluggish shifting than normal but now it,s back to normal.

 

^ That's actually exactly what I was thinking and hoping it is. Because I had to suddenly go out in between my intake install, so the battery was left unplugged for about 5-6 hours.

Hopefully it's just a matter of the ECU learning everything again. Thanks for the input.

 

Hopefully the ECU just needs to relearn everything, Fab! That would be quite the mystery to why it just stopped working!

 

maf dirty, maf installed backwards, air leak after maf, maf disconnected - something is causing a lower than normal calculated load, which is transmitting that to the TCM. You will be wearing the clutch packs if the calculated load is inaccurate so try to get it fixed soon...

 

^ Hmmm, probably a dirty MAF, although the car's idling just fine. I'll have to pick up a cleaner. I have to switch back to my polished intake anyways so I'll check everything out, thank you.

 

So I swapped out my intake again today, used a MAF cleaner spray and made sure everything was hooked up right. Took the car out for a spin and it seems to be back to normal, nice quick shifts again .

Not sure if it was just the MAF that was dirty, or if I somehow managed to incorrectly install an oem intake, lol.