I have a 2001 doge dakota sport rwd and the rpm's are low, some times the truck will stall shifting from reverse to drive. idels around 500 rpm and drops to shift out of park or neutral. can you please help me out.

the vehicle has gone into limp mode as there is an electronic fault,try disconnecting battery overnite and reconnect in morning if problem persists you need to have diagnostics done to read the fault

Check the rpm in neutral should be around 800-850, this should drop to 500-550 in drive or reverse.

You lost your 2-4 and that is normally the Band or Drum

Cam position sensor. I believe that is what it is called. I had the same issue.

first check for vacuum leaks, then check idle air control valve.
Please see my tip at http://www.fixya.com/cars/r7427423-fix_poor_idle_high_idle_stalling_fuel . These are generic instructions. If you getstuck or need specific instructions for your car, please get back to me with model, year and engine info.

I presume it's an automatic--could be low fluid or internal pressure problem in trans. Check fluid level when warm --read dipstick as to whether to put in park or neutral when checking. Otherwise,take to shop for testing.

Try unhooking one of the battery cables and leave it off for at least 20 minutes. When you hook it back up the computers should re-boot. That has solved problems for me with heater, interior lites, power windows, AC, day time running lites, power mirrors, fast idle, rough or slow shifting, CD player, and wipers on GM autos and S-10 PU and Dodge trucks. None of the switches are connected to the device they control anymore. The switch tells the computer to open the window and the computer send a signal to the window motor. When the computer gets confused strange things will happen or not happen. Of course you may have to re-set your radio stations.

In general, yes. This is a carb tuning issue. Another possibility is a vacuum leak somewhere, but most likely, it's a carb issue. You'll typically see your rpm drop a bit when you put it in gear, but that it sometimes stalls out points to a carb issue.

spark plug cable is lose or one spark plug is faulty.

i have a 1986 chevy corvette, when you fist start the motor it idel fine, when it wormes up, it ideling rough and RPM jumps up and down, and you can smell gas when you fist statrt it but there is no leaks,also when your driving about 45mph it puags down until you push it and then runs fine. please help me with this issue.