Speedometer fluctuates after driving 35 MPH?

Oh, I also bought a second set of speed sensors recently, as they were inexpensive, and I thought maybe that would help, or if the alternator were originally bad, that could have hurt the first set of sensors I put in. But I have NOT put these in yet. I am concerned that something else electrical could harm the sensors. I don't want to install these and have them get zapped if that is possible.

Sounds good. And no real hurry - ha. I have endured this for a year, and after reading everything I can on this issue, I have not seen a reliable fix by anyone, ever. So, it's a holy grail type of issue - when solved, it will be a big deal. Or at least for a lot of folks still driving these relics.

BTW, haven't replaced the battery, as discussed, that battery is getting pretty old, but still starts reliably. Long while back, had a bad relay (now replaced) that was causing parasitic draw of power that drained battery several times, had to jump-start and recharge batt several times before I found that issue and fix. Maybe that harmed something back then. Oh, and I have checked the ground points in the engine bay. All look clean and beautiful, not crusty, loose or dirty - they look pristine, tight and original as the day the car was built.

I have not taken my car to a Chrysler dealer, as I've just heard too many completely clueless and $$$$ failures on this same issue from those that went that route. But, if there is no other recourse, I may have to try that - someday. But let's see what else may be suggested. Cheers!

Interesting. I did see this idea (lots of reading on all possible issues on Internet) and I remember this idea - and it's why I originally changed to a brand-new alternator. But I was not given a simple test like this to try. So, I replaced the (original/old) alternator and put in the new one. And the issue was still there. It's possible but unlikely that the new alternator has a bad diode, unless there is something to cause that! But I'll try to run the AC check and see if there is an AC reading.

2 Questions:
1. The battery is tough to get to, behind the left front fender wheel well. And, I'll have to jack and allow FWD wheels to freewheel under acceleration. So, can I check at the + positive post (recharger point) in the engine bay (and ground) to watch for AC current with car wheels accelerating?
2. Can this check be done while driving the car? Reading any AC from cigarette lighter, or from fuses point in the car?

Just seeing if there is a simpler/safer way.

Oh duh. You prob mean just put car in neutral and rev the engine, right? No need to allow wheels to spin. Sorry, I just jumped to that. Please confirm.