I personally shift at around 3500 rpm.  3000 is a little too low, 4000 is a little high unless I'm climbing a hill.  One this is for certain, at least for the 2.0 is that it doesn't come alive until you hit 3000 rpm, after that it pulls real strong, right on up to 5500 to 6000 rpm easy.  (I still don't visit the 6500 rpm red line that much.    HTH, Dave

ps. also, I notice that the gear ratios are a bit diffrent going from gear to gear.  There is a 2000 rom drop going from first to second (if I shift at 4000 rpm second is at 2000 rpm.) but 2nd to 3rd and 3rd to 4th have aournd a 1000 rpm difrence.  then 4th to 5th it's about a 500 rpm diffrence.  Don't know how th eolder trannies are.  This is a bit of a diffrence from my 90 Trooper when the big jump ratio wise was going from 2nd to 3rd instead of 1st to 2nd like on my Tracker.  Have fun,  Dave