High RPM problem

I have a Dodgce Grand Caravan 2000 with 3.0L V6. Recently I observed that it is going at high RPM even in low speeds. I can hear the engine roaring at 45 MPH speeds. It obviously decreased the fuel efficiency to 13-14 M/G. I got it checked at a repari shop. They did fuel injection service, and also reset its computer code which went from 1 to 2. They also did repair on trans coolant rods as they are leaking, becuase of which the computer might go to 2, which might be the cause of high RPM (Running at low gears)!... BUT THE PROBLEM STAYS.. Any inputs?

Thanks in advance - KP

Is you Trany shifting as it should or is it high reving because it is not shifting? If it is not up shifting into a higher gear at the right point when it should, the speed sensers may be the problem. They cost about $40.00 each there are two and are not two hard to replace. So the repair bill shouldn't be too high. Sometimes they will test out as ok but are not. This seems to be a fairly common thing with these vans. Hope that it is this because the alturnative repair if it is the trany can be a much bigger repair bill ($2000-$3000). I had the same probelm as I have discribed (high reving and not up shifting) with my Chrysler T & C and had the sensers replaced, it has be shifting fine ever since:iceslolan. Don't continue to drive your van like this as it may damage your engine.:nono:
Ride On, digimon :smokin: