So, I have searched this problem (both on this forum as well as the rest of the internet) to no avail.

Car is a 2003 I35 with 101,000 miles. Alternator and battery are maybe 1 1/2 years old. Regular maintenance and no aftermarket parts. No accidents since I've had the car (over 50,000 miles ~ 3 years). No major work done, just regular maintenance.

Here's the scenario: Alternator (and brake) light have been flickering and sometimes staying on for a month or so. This dash lights came on about 8 months ago, than went away until recently. As for this time, there is no pattern to when they come on (cold, warm, accelerating, braking, no certain speed, etc.) Keep a voltmeter in the trunk, and have taken many voltage readings (between 14-15 volts) and there's no pattern there either, light is on or off randomly. Car drives fine whether the light is on or off.

Left work today in the afternoon and car started up normal. No dash lights on. Came to a stoplight 1/8 mile away. When the light turned green, I hit the gas and didn't go anywhere. Engine would not rev while in any gear. Alt & Brake light were on, as well as TCS off & A/T Check lights. Put it in park and the engine would rev. Turned the car off and tried to start it again and it did start but with hesitation. Turned car back off. I hooked up an almost dead jump box (battery level for the box was at 1 out of 5 bars) and the car started. Voltage was low (13 and under). Engine would now rev in gear.

I ended up driving home (15 miles) with the jumpbox hooked up. Got home and the battery level for the jump box was now fully charged. Car's battery Voltage was normal. Alt & Brake lights flickered randomly on the ride home. Car drove normal. After unhooking jump box, no dash lights came on, and I was able to start the car. Car ran for about 20 minutes (with headlights on) with no problems or dash lights coming on

Has anybody had an issue like this before (doesn't necessarily have to have happened to an I35). Any ideas? And TSB's out there that may relate? Nothing I've found relates. Any help is greatly appreciated.

to NICO!

I really don't have a whole lot to offer here... maybe one of our techs will stop by with something more concrete. It really does sound like an alternator or battery problem... more likely an alternator. I know you say you've tested the voltage from time to time and it's always in the 14-15VDC range. Maybe you could rig up a cigarette lighter plug to your volt meter so you can monitor the voltage in real time? I had an alternator fail with an intermittent drop out once, so I know it can happen...

Just for fun I would recheck all of your electrical connections at the alternator, battery, etc...

Good luck!

Heath

15 volts is way too high......something not right with that alternator,have it professionally tested/