I changed my fuel filter and my spark plugs and wires, and checked my
distributor cap and rotor during a tune-up.  When I went to take the rotor
off, I took off two screws that held the metal part in place (the metal
circle around a metal star that rotates inside the distributor, not sure of
the name of this part) thinking that it held the cap in place.  That thing
got turned all around, so I put it back in what I thought was the right
place, but not before turning the crankshaft to watch the distributor spin
(simply out of curiosity).  Now I'm thinking that since the distributor is
in place, there's no real danger of changing the timing by turning the
crankshaft, because the rotor is designed to fit on the distributor only one
way, right? And the distributor should still be in the proper position.  So
I put everything back together, and I'm now getting a loping/surging during
soft accelerations (but when I put the pedal to the metal, it accelerates
fine) and an occasional backfire (popping sound coming from the exhaust,
that's backfire right?).  I've been having problems with the alternator
making a loud rumbling sound (even though it is still putting out enough
juice to run the car and keep the battery charged).  Is it at all possible
that the alternator is causing the loping/surging?  I'm pretty sure I got
the distributor and distributor cap back together properly, but this problem
sounds very distributor/spark-plug-esque.  I'm hoping it's the alternator
(who's been making that rumbling sound for some time, but now that new spark
plugs are in it, the sound is more pronounced).  Any ideas?  Thanks,
-Ben
PS It's a 1990 V6 3.1 L engine