Car was running fine and then started running rough on 1995 Toyota Corolla

Has 200k on it auto trans,all oem parts,just had it smogged 2weeks ago,it was running great,and then all of a sudden,running rough in gear and neutral,I pulled the #1 plug wire,got good spark,little change in engine pulled #2#3#4 and engine changed dramatically,checked plug itself looked good

Asked by for the 1995 Toyota Corolla
Any oil on the plug or wire anywhere?
Nope clean and dry showed good burn golden in color
Vacuum leak, low compression, defective plug or injector problem.
I'm gonna try and check the plug,then timing,then compression,hope its not that though,maybe get lucky with vacuum leak I'll let you know what I find thsnks
Ok, timings good,plugs and wires seem ok, compression is good on all cylinders all around 160.put everything back together,seemed to run fine,after a few trips up and down the road,it started doing it again, my alternator is squealing a little, do you think that this could cause a misfire? When it cools off I'll try and disconnect the negative cable on the battery to see if it dies