Just purchased a 03 350z with 87xxx miles for $4000. Within the first day I found a big problem.
So in the morning or when the car is cold, the car works fine. After about 20 minutes or when the car is warmed up the car accelerates very slow. I'm guessing limp mode. I get a code for knock sensor but I replaced it, still same code. Spent 3 days reading everything I could find. every thing I saw said a different solution. Before I spend my money I would like a 350z expert to assist me. Im very stressed with this issue. Any info is better then nothing.
So this is what I can tell ya: most came with the car already...

Aem intake, kenwood radio, one sub with amp, led around the door, z led tail lights, viper alarm, new knock sensor, all new gaskets, spark plugs,new belts, new pcv, hid, Automatic, 10w30 synthetic, 93 gas,

Here are the problems that might be the cause:

Tail light most led bulbs are out, engine ticks at start up and holding high rpms, the viper alarm/blue LEDs/radio setup was all done by the same guy and the blue led was not working... I got them rewired because they were poorly installed so thinking the alarm and radio are poorly wired(wasn't grounded properly), when the volume is high for the radio my volts drop and the battery check failed at autozone, when I turned the radio off the battery passes, some corrosion on battery, problem still happens when radio is off, sometimes I notice the rpm gauge drops to 0 and then pops back up I think during gear changes or when I let go of the gas, air intake filter looks old, fuel gauge is not working planning to replace the sensor, no other codes besides the knock sensor,

I'm sure I'm missing other things. I hope I get help. I'm in need please help me. I live in Long Island queens border and willing to drive for advice 24/7 I'll sleep later...

 

Aftermarket taillights are known to cause major electrical problems.

1. Install OEM tails and hopefully, that is what is causing the issue
2.Check the wiring on the stereo and alarm
3. Recheck battery after new lights/ buy a new battery

 

Good luck. I have to wonder about the condition of the Z you bought for $4000.

 

In the morning, this car is a dream. My friend is having money trouble so I got a good deal for it. Just this one issue.

 

Thread moved to Maintenance & Repair

 

Check the timing on the crank angle sensor. I had a R32 Nissan Skyline once that did that. In the morning it was a beast, but once it got hot would activate the knock sensor and go into limp home mode. Timing was out 15 degrees.

 

thanks for the info, thank everyone for helping and viewing. I'm so upset my car runs like this. I know he's hurting, I wanna make him better

I will talk to the previous owner to see if he had anything done in that area

Ok talking to the prev owner he said he changed the camshaft position sensor. He said code came on, he replaced it, oem. He said to ask "would the crank angle sensor go off if it is off?"
I first asked him if he changed it, he quickly said "yes in bay 2" then said no, actually it was the camshaft position sensor and a spark plug.

Reminder, I had the engine apart when replacing the knock sensor, spark plugs, engine clean out, new gaskets.
Thanks

Is there more then one knock sensor??

 

Got a code for knock sensor, I replaced it and code still says knock sensor.

How many knock sensors are there??

Any ideas on what could cause this??

Limp mode is killing me. Can I drive long distance in limp mode?
There is a ticking in my motor. Thanks for the help

 

Ok, maybe I'm not in limp mode... Would I be able to redline in limp mode... Don't think so.
Basically the rpms go like this 2.1,2.2,2.3,2.2,2.3,2.4,2.3,2.4,2.5,2.6,2.7,2.6,2.7,2.8,2.9, 2.8,2.9,3.0,2.9,3.0 ect.. In the morning I see about 14.5 volts. Car runs beautiful... When the volts go to 13.9 the car runs bad... I use gas quickly and my gas gauge sensor is not working properly.

Someone said a bad vacuum... Another said bad intake sensor, another said fuel injectors, coils, another knock sensor, the list goes on.

When I'm in sport mode(manual part of the automatic) and downshift to second it feels like it's slowly going into neutral then popping back into second... I've had a stick car before that's how I know...

I went to buy taillights, guy never showed up. I'll try tomorrow.
Side note: any way to stop this clicking in my motor?? Lucas good to use?

Thanks everyone for at least reading. I hope I didn't post this wrong moderators. I already got warnings

 

Dude just bite the bullet and take it to a dealership. Diagnostics will be around $100-125. You're doing what we call in the industry shotgunning.

 

Guess I have to. I'm sure it's gonna cost more then that. I'll try tomorrow morning.

 

It will only cost you more if you agree to it.

They start with a basic diagnostics. Most problems can be found within that diagnostics procedure.

In rare cases, which you might fall into, is if they have to find a wiring problem between some sensors and they have to trace and hopefully repair. When I come across this problem I usually ask for 2 addition hours in diagnostics. If they find the wiring problem and it is repairable then they'll repair it or even ask for a couple more hours in labor to repair it. So any where from 300-600 bucks.

Or if wiring issue is too extensive then they'll probably just recommend a wiring harness. That'll be too expensive. If that's the case the take the car home and start following every wire until you find it. Or but a used harness.

If I was to guess you have a wiring issue.

 

Ok. I'll take it there tomorrow, I'll update when I'm done

 

Ok, so I'm driving to the dealership and wanted the problem to start before I had it tested... One hour of driving, the car is fine. Fml, just my luck. Car wants to drive fine now. But now the CD player and usb are not working. So I'm going to assume it's the radio wiring. I don't believe this. Car wants to act up until it's to the dealer, now it wants to run fine. I will continue to update as I get things done. Tail lights should be here today. Going on a three hour trip to New Jersey tomorrow. Wish me luck

 

Could be a bad ground. Check the ground wire on you knock sensor (be very careful not to introduce voltage into it until you figure out what current the knock sensor uses since it's connected to the ECU)