I have a 2003 350z with 164k miles, performance or touring edition im unsure. It has the VDC, seat warmers, and navigation. I'm having some acceleration issues. About a month ago now, my car started to feel like it had been falling into limp mode. I hit the gas and the car accelerates very slow. Occasionally the car will kick it regular mode and when I hit the gas it takes off normally, however, this is only about 15% of the time now. The other 85% of the time my car feels like its in some sort of limited mode.

NO check engine lights are on, and there are no fault codes stored. also my cruise control will not set; not sure if this has any relation.

MODS:

Nismo CAI
Upper Plenum Spacer
Stillen Catback Exhaust
Stage 1 Clutch

TROUBLESHOOTING:

I have changed all spark plugs, no effect. I had a dealer like computer diagnostic machine hooked up. The upstream left o2 sensor was dropping voltage from around .80 to .04 which was different than the right sensor which was holding a steady value. this led me to change the left o2 upstream sensor, still had no effect.

My next atempt is going to be to change the KCOCK sensor, as this is what someone last suggested where I work on my car.

help? Thanks, Nick

 

Hey Nick,

when you installed your CAI and/or the plenum, did you do the throttle body reset procedure? What about resetting your ECU? Are you 100% sure you reconnected all the vacuum hoses? Might you have a leak somewhere along your intake? Is your MAF sensor clean and positioned correctly?

I would visually inspect your intake plenum, clean and make sure your MAF is placed correctly and then reset the throttle body and ECU.

Google the steps to reset your TB/ECU and if you can't find it, I have it somewhere.

It could be your knock sensor on the fritz kicking your ECU into safe mode but I would try the (free) throttle body and ECU reset before tearing off your plenum to replace the knock sensor.

The fact that you arent pulling codes makes me wonder -

 

Have you changed tail lights or tires lately ?

 

late response,

I have removed and cleaned the MAF sensor a couple weeks ago, no change. I did the TB and ECU reset, no change. The Engine light blinked like it was supposed to when resetting, so at least that's good news. I haven't had time do replace the KNOCK yet.

THE MAF sensor: I had someone tell me that I had my MAF installed backwards, this guy thought the arrows on my intake were supposed to be facing out instead of in. I figure the arrows should be pointing in the direction of airflow, but I took his advice and tried flipping it around, the car started and immediately died. I'm assuming if you put it in backwards your car won't even run. Anyways swapped it back around and it started back up normally.

Why the the tire and tail light question? No I hadn't changed the tires since this problem started, but I today changed them because the inside front tires were super worn.

I have a rear brake light out that needs to be changed. Are you just trolling? lol

 

I mentioned tires because some people install the wrong size tires and trip TCS /VDC badly because the installed a weird size.

Tail light bulb, these cars are known to go into a weird limp mode like you describe with aftermarket taillights. I bad bulb could easily mimic the condition your car does not like.

 

If I change my brake light and my ENGINE works.. I will never own another Nissan

 

So I still thought you were messing with and I did search for tail lights engine problems... behold I found a 8 page long post about someone troubleshooting everything and finally fixing his car with a tail light.. ive been shooting for about a month.. atleastl. im gonna go change my brake light bulb... now, brb

 

well that wasnt as easy as it looked.. an hour and one broken tail light clip later i have the wrong bulbs. itll have wait for tommorrow. funny thing is, only one was out last time i checked, now both bulbs are blown. i have a funny feeling you hit the nail on the head with this one terras.

 

WOW a month and a good 300 dollars later, all I had to do was change the brake light bulbs.

What a perfect storm, when your engine dies, who cares about changing the brake lights right?

THANKS TERRA!!!!

 

So, that means you are selling your Z and no more Nissan the rest of your life, right ?

 

No problem.