ryanisfast

So, just recently I noticed that my CHECK GAUGES light flickers off and on at right about 1400-1500 rpms when I'm driving. At the same time I notice my battery voltage needle start to move towards the red, but not all the way, just acting like it wants to right when I hover around that certain rpm. I also notice it does it sometimes when I'm giving it a lot of gas only sometimes at certain rpms.

What the hell would cause this? It doesn't seems to run any different when it's happening, it's just weird. Could it be a loose ground or something and why would it only do it at 1400 rpms???? I'm totally lost on this one. Lol. Thanks for the help.

RamAir95TA

iTrader: (2)

Have your alternator tested.

ryanisfast

Ok thanks. That's a good idea.

qc97z

iTrader: (9)

Besides having the alternator tested, check all of the connections to the battery and grounds.
What COULD be happening (although it's a stretch) is at ~1400 RPM your drivetrain is radiating a "resonant frequency". Every object vibrates at a certain resonant frequency. If something is loose, 1400 RPM is making it vibrate and cause an intermittent connection.

SS RRR

iTrader: (2)

You can test it yourself w/out taking the alt. off. Take a volt meter to it. It should read a steady 14.5v. If it reads any lower then it's most likely bad. I've read where alt. testing at auto parts stores isn't always accurate. You also may have a slipping belt and/or worn out belt tensioner. Do you have an underdrive pulley?
Actually before doing any testing make sure the belt/belt tension is good.

qc97z

iTrader: (9)

^^ I've never taken an alternator in to test, strictly for the reason SS RRR stated. Taking of the alt. just to get tested sucks. With a standard multimeter, read the voltage with the car running for at least 5-10 minutes, and have someone else in the car to do whatever you need to replicate the symptom. Alternator needs to read ~14.0 Volts or better, 14.5 seems a bit high.