Hello, I have a 2003 350z and I've been having problems, randomly when I'm driving the tachometer has been going crazy going up and down. I was driving home from work one night and my headlights turned off by themselves and the blinkers would randomly work. now my battery died for no reason that I know of, I did not leave headlights on or the stereo. Has anyone else had this problem?

 

Ima take a wild guess at the battery being bad, causing the other problems.

 

I just went through this problem.

1. Check your belts first, because it could just be very loose, and not turning the alternator enough. Just tighten the belts

2. If the belts are fine, test the alternator. Autozone can do this for you.

3. If the alternator is fine, then it's the battery.

 

Agree. Batteries go dead for a reason. Either the battery will not HOLD a charge or the battery is not being charged.

 

The stuff with the tachometer was happening like a month or two before the battery and I haven't been able to take it in because I live in a small town. I took it in once into a local auto shop and they said they got some strange codes from the computer, they cleared it out and it worked for a while but now it is happening again. I forgot to mention before when it starts happening with the tachometer the car does a strange jolt almost like I'm being rear ended.

P. S. I really appreciate the help and your time!

 

Solve the battery problem first. Then figure out the tachometer.

 

It could definitely all be your battery problem. When it happened in my automatic, my tach went crazy, and would shoot from 2k to redline. It also caused my transmission to SLAM into gear for drive, and stick in 2nd gear when it did that. Started up fine, but ran horribly. I also got a CEL for faulty gas cap?
All because of a loose belt.

It could take a while for the battery to just die. It could be that the alternator is getting turned just enough to start and run like crap. Maybe took a month in your case.

Just fix your battery/alt and see if it helps. You have to anyways. If it doesn't, go to autozone get them to check for codes, then we can figure out whats really wrong.

 

Sounds like maybe alternator.

 

Chances are, if it was the alternator, the car would die while driving. I say it's the battery. How long have you had the current battery?
If the battery has never been changed, I can almost guarantee that it's shot. I had an '05 with 50k miles and had to replace the battery.

 

Thanks for the help guys I'll get it checked A.S.A.P.!