Have a 1998 Dodge Ram, 46RE transmission, Sometimes when starting to move in drive range will notice the RPM's running high, a tap on the gas pedal brings the RPM needle back to normal range, is this a Control mod selinoid and Pressure sensor prob ? Or is it a indication of trans failure ?

Is the fluid level full?
When was the last time you serviced the trans? was the proper fluid used?

Next time you let it sit for a while (overnight to a few days), after starting the engine try putting it in neutral for about 5 - 10 seconds then put it in drive.
The 46re doesn’t pump fluid in park, the check valve in the cooler line may be fubar so the delay in movement & rise in rpm might be caused by the time it takes to pressurize the system.
If that fixes it or helps your problem, remove the check valve. There are kits for this or cut it out use high psi hose double clamped on both ends.

If it has any other symptoms such as slipping, shuddering, mis or harsh shifting it is bad news.

If a sensor is bad / malfunctioning it should set a code & possibly give a check engine light. Best to get the codes checked by someplace with a reader capable of retrieving trans codes.

Rustler,
Thanks, will follow your directions,
I have recently changed fluid to a Chrysler Purple fluid ;), there are really no other know problems showing, , no chk engine light., will have the codes checked

As long as it is an ATF+4 fluid and the filter was changed it should be okay.

Past service history will have a lot to do with the following.
With regular service intervals using the correct lubricants the chance of the below is less.

If it came new filled with ATF 2+ or ATF 3+ and you recently changed to ATF+4 frequently the +4 will thoroughly clean the internals which will leave contaminate deposits in the filter.
It certainly can cause the check valve to be sticky or inop.

If the deposits are heavy enough to impede flow or plug filter it can cause trans to act sluggish engaging forward - reverse, in worse cases slip. In cases of unknown or poor maintenance habits or ignoring symptoms of flow restriction it can cause premature trans failure if left without service.

Good news is, when you pull the pan & filter a tech that knows how to do it correctly can tighten/adjust the bands, fresh filter & fluids & you'll think you got a brand new trans for the cost of a band adjustment & oil & filter service.
Most folks with good mechanical aptitude & the right tools can adjust the bands also.