98 impreza lights pulsing at idle

[scooby88]

I just bought a 98 impreza and noticed today that the headlights and taillights are pulsing at idle, the pulsing also seems to be in rhythm with the idle...if the rpms are higher (steady throttle or driving around), the pulsing seems to stop, so in other words it improves with increased rpm. I also have a flashing battery light on the cluster every now and then (sometimes it doesnt turn on)

Ive cleaned the battery terminals and the ground and it didnt help (terminals were pretty clean as is), I put a multimeter up to the alternator and noticed that the voltage drops and raises within a volt as the car idles (about 14-15 volts).The previous owner said that the alternator was replaced a few months ago and holds its charge, hasnt ever died, also the car has new spark plugs and wires

Im going to take it to have the alternator and battery tested to try to eliminate those as sources of the problem, but Im interested to see if anyone has had a similar issue or any idea of what would cause this...It has new plugs and wires but I dont think the ignition coil was replaced, so maybe that would cause it?

Thanks for the help

[Seraphinwolf]

Look for other bad or loose grounds and stop by a auto parts place and have them run a free check of the alternator.You may want to just replace the battery anyways. Next good option that will help no matter what the actual cause is is a grounding kit that grounds to the chassis the battery, alternator, block, and any other main power points.

[shtbxr22]

sounds like a poopski alternator. test, test, test!

[scooby88]

got the alternator and battery checked today...battery is good, alternator is generating too much voltage...

would this cause the pulsing lights if the system is being over loaded?

also noticed that the taillights pulse pretty much all the time when they are on (even when the battery light isnt flashing in the cluster)...and also after driving around for a while today I noticed that the battery light stopped coming on...I think the harmonic balancer pulley is bent as well (wobble in the pulley but its tight), which im wondering if its contributing to this issue...engine runs smooth though

[Seraphinwolf]

"overproducing" isn't an issue. You probably just have a power draw from some bad or some other reduced contact on grounds. Seeing how both were checked and fine I would do spark plugs and check your plug wires and coilpack then do a grounding kit definitely. It's a 12 year old car at this point. Grounding point start going after a while.

[scooby88]

cars all fixed...I fixed the pulley and also found some hack job done in the aftermarket radio wiring

[Seraphinwolf]

Well there was your likely power draw. Especially if running an amp and subs.