4th gear O/D 4th gear not working in vr

[nathsvrbt1]

i have a vr v6 commo and i havent noticed last week wen doin 90-100km on the highway it does go from 4th into that sorta overdrive 4th that drops the revs down heaps
so i am doin like 2200 rpm in 4th at 100km instead of the usual 1800-1900 anyone have any suggestions as its satday nite and no mechanics open till monday and im really starting to get the SH!Ts
i have also noticed that every time i start it up any time of day it builds revs up to 1500rpm then slowly lowers to bout 1000 rpm on idle in P or N
any help will b greatly appreciated

 

[hako]

Not sounding stupid but have you checked the economy/power switch is working and not stuck on power

 

[sixshooter]

When was your auto last serviced ?
Is the fluid level correct ?
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http://www.usatransdoctor.com/DomesticGMCSELECTandAnswers.htm#4L80E