Engine Code P0354 and Weird symptoms

[DoraDaExplora]

2 weeks ago, my engine would start trying to stall when I took my foot off the accelerator when pulling up to traffic stop, or quickly taking foot off of peddle ( when revs are low ) The RPM needle would dip to about 400rpm, buzzer come on, Engine would either stall or nearly stall. Last week while doing a 400 mile trip, on the way home at night, We where driving along at 70 mph with normal lights on, then when I flicked on high beams, whole car jolted, engine died for 1/2 second, buzzer on, lights dimmed, A/C slowed down etc... Had A/C on, Stereo, lights etc... So I started flicking the High beams on and off, and it kept trying to stall every time ... Once I left high beams on, no problem, just when turning them on. Also when driving along, If I pushed windows up button, it would do the same, ( with window fully up ) Happened once before, also after long drive.. Once while flicking the high beams on, The RPM needle peaked at 7000 rpm, ( engine was only doing 2,000) and speedo maxed out also... Power surge?

No problem with acceleration. Or general cruise speed.

I have the Code P0354, ignition coil D. The other morning, I put on the multi meter, reading 13.5v when car off... When car on, with everything going, lights, beams, stereo A/C etc, the volts where dropping down to 11.9 - 12.3 and engine would slow down etc, with more load on it... Took car to shop, mechanic said Battery test, starter test, charging test came back fine. No other codes.

Would the Ignition coil problem be related to the stalling etc, or is the Alternator on its way out? Any recommendations or links would be appreciated...

2003 V8 Explorer Limited.

 

[DoraDaExplora]

With the code P0354, would I just change Coil, check spark plugs or change everything. IE:Leads, plugs etc. Or is the code specific to just the actual coil... ( could do with lead replacement etc ) Me and wife are novice mechanics, But are going to try and give this issue a crack...

 

[Number4]

Sounds like your alternator isn't handling a load. I'd suggest having another shop check it out.
These cars seem to be sensitive to a slightly off alternator.

Edit: if the alternator can't provide the required juice, other items may appear to be bad as well.