i drive a 98 civic ex 2 door....just randomly the other day my electronics all but the audio started pullsating,even the spedometer stopped working (brand new speedo sensor), and the tacometer is screwy. i replaced the alternator and it is still having the problem. both alternators tested to be good. i've redone all the engine and electrical grounds, and checked all fuses and relays. but heres what gets me. if you unplug the alternator, and let the car run off the battery, everything is fine and normal. and it only does it when the alternator is hooked up and the engine is running. i've even tried a friends new battery. which the battery is also not getting a charge from the alternator. is this a common problem or does anyone have any other ideas of what might be wrong? thanks for all the help anyone can give to me!