95 plymtouh neone 67, 400 miles.i hanged my oil last week, exon superflow, and had a new fram tough guard filter. i cnage oil every 3months, manufacturer books says to change at 3 months or 3 ,000 miles,.i out 3,000 miles a year on ym car, so to ensure theirs good oil, less contamination thats why i do such shrot changes. okay since ive used tough guard, most of the time, my car has rum at rpm, hot, form stop to go, then kicks back to normal. i instaled a fram extracare filter in,a nd the high rpm almost went away! could the tough guard, be the cause? or someting else? i am using moblie 5000 conventional now( my car LOVES this stuff so far)!