Tach jumps and engine stumbles, under electrical load Options

[mikew04]

A few weeks ago I had to get my car jumped; came home and checked voltages: a little over 12 running, a little under off. Took it to advance auto and they confirmed I needed a new alternator. Ordered a new one from 1sttoyotaparts, had to wait over a week for it. Got one for the auto for the extra 10 amps.

During that week my car didn't need jumped but acted funny under high electrical load, mostly on the highway. When hitting the brakes, turn signal, windows etc., my tack would jump up and flicker around and the engine would stumble ever so slightly. Even more so with cruise control engaged. Sometimes would do the same thing when stopped at a light holding my brakes. On occasion I would go to start the car and everything would die til I took the key out and tried again. It would (slowly) start but my clock and radio were reset.
I figured this was all related to the alternator, so I waited it out. Got the new one in; it was showing 14.5 volts and the problems went away. Sweet.

Started acting funny again about a week later. Same symptoms, but occasionally the check engine light came on for about 4 seconds when the tack is flickering.

It's throwing a code 14 - ignition system. Now I'm only showing 12.5 volts while running. Connections to the alternator look good (confirmed with multimeter,) belt is tensioned right. All grounds are good and the Big 3 have been redone with 4ga cable. Plug wires are seated correctly. Distributor rotor and cap replaced within the last two years. The ignitor ground is also fine. Back to having slow startups even though the engine is putting out 720CCA (according to the machine at advanced.)

Anyone have and ideas? This is driving me nuts and I have no idea why this is only happening when the electrical system is under load.

[stephen_lee]

check voltage drops w/ multimeter.

b+ on alt to battery positive terminal should be <=.3v
everywhere else should be <.2

[mikew04]

Checked those, all are at or under 0.1v