No power, then runs fine. What gives?

[BigSargeSS]

Here's my issue. I will be driving my car and it looses power. The car starts to shake and miss. Then after a couple of minutes it seems to run fine. Next issue when this happens the odometer and trip indicator flashes. While this is happening all of the lights interior and exterior are all dimming. Also I can here a kind of knocking under the dash, I thought it was a rod knocking but checked while engine was running and it was not knocking. Lastly, while the knocking is happening I can hear it pulsing in the radio. I know alot of issues with a really brief description.

I'm thinking it is the alternator going bad, but it is charging at over 13 volts according to the gauge. I was also thinking maybe a bad ground or computer going bad. Any suggestions? Thanks in advance.

Big Sarge

[0rion]

check all the cables for corrosion first...that's a simple place to start.

[Redphoenix1998]

Sounds like a bad ground somewhere or a short to ground in the system. There's a critical ground behind the drivers side cylinder head, check to make sure it's not loose. Check your cables for corrosion like orion said and all your engine grounds. Also check the voltage with a DMM from the alternator cable to the B+ on the battery to make sure that is the voltage while running. Gauges can lie believe it or not. Oh also check the ground strap to the alternator

[lvbroham1]

Sounds like a bad ground somewhere or a short to ground in the system. There's a critical ground behind the drivers side cylinder head, check to make sure it's not loose. Check your cables for corrosion like orion said and all your engine grounds. Also check the voltage with a DMM from the alternator cable to the B+ on the battery to make sure that is the voltage while running. Gauges can lie believe it or not. Oh also check the ground strap to the alternator

When you said your radio starts making noises the first thing that comes to mind is a bad ground.

[BigSargeSS]

I will be going over all of the grounds this weekend. Does anyone know where I can get a gm repair trouble shooting manuel in pdf format? I find that it is easier using them. Thanks for the advise, just wanted to make sure I was looking in the right direction.


BigSarge