Low power- charging issue?

[Blimited03]

Hi guys,

I have an 2003 Limited 4.6L V8. Not too long ago, the "Check Charging System" indication came on the alert center and the battery light on the dash as well. I replaced both the battery and the alternator and both have tested OK. There is no battery drain or anything like that happening but the light and message stays on. However, when I let off the gas, particularly at very low speeds the headlights and interior lights will dim and the engine will bog down almost to the point of stall, for just a second or two. Anybody out there experienced this or have an idea if the two are related? Thanks!

 

[DJ]

I'm far from an expert, but IMO it sounds like a bad hookup. I would double check all your hookups, make sure that they are all nice and tight. Specifically the charge lead on the alternator. Make sure your battery clamps are nice and clean too. If your still having issues, hoom up a voltmeter to the battery (most car parts places will do this). Your alternator should ivey putting out a little over 13 volts.

Perhaps its a loose wire that is grounding out?

Sorry I can't be more help.

 

[Sedition]

It sounds to me like the battery positive is momentarily becoming disconnected from the electrical system or is becoming loose enough to cause a problem. Check for a hairline fracture on the positive terminal connector its self.

 

[Blimited03]

Thanks guys, I think the issue is a little more serious now though.

Here is what is happening now;

The truck died on me going down the road, I was able to bring it to a stop and then restart it no problem. However, the idle was revving up past 2000rpms and then dropping well below 1000rpms almost dying again. I managed to get it home and found that sitting in park, I can give it a bit of gas and the thing will rev up over 2000rpms on its own for a few seconds, then it will down well below 1000rpms again almost dying, then cycle back up to 2000rpms again and keeps cycling like this. When in drive and I give it a little gas it will rev on its own at about 2000rpms, it does not jump back down and start to bog down again. I have replaced the Mass airflow sensor and the TPS and the Idle air control valve, and now I'm at a complete loss! Anyone experienced anything like this??