2000 ST350 Losing juice?

[tegger]

On my 2000 350, when the lights are on, everything is fine for a while. But, while cruising for a while at almost the top-end of speed, the lights will suddenly dim and I'll lose a little power. Let off the gas and everything is back to normal for about 20-30 minutes and then it does it again.

We noticed it doing this when we were running it back to the trailer after a parade a week or two ago. Around town, I can't seem to get it to do it. But, we run it over to the sister-in-law's and it'll do it. (It's about a 20-25 minute ride to the in-law's.)

I can't find anything wrong. It was recently tuned up with valves adjusted and all.

[COURTESYCART]

I would put a volt meter on the battery and go for a drive until it acts up. See if the voltage at the battery drops off. If it does than i would say you have a bad voltage regulator. I have seen them quit working after they get hot.

[tegger]

I'll have to try that out. It doesn't always do it though. That's the annoying part.

[tegger]

I finally was able to try this out over the weekend.
The voltage at the battery was holding steady at 14.2vdc with nothing on (I have a battery isolator switch). When the car was running, it would hold steady then suddenly drop to around 9vdc. Let off the gas for a second or two, press it again and voltage was fine around 13.5 to 14.3vdc.
To me, that sounds like the regulator from the descriptions I've seen.