Ford Repair: Ford Ranger misfire, leakage test, ford ranger

Question
I have a 2004 Ford Ranger v-6 3.0L   The #5 cylinder misfires below 1,000rpm.  Above that it runs fine.  When it is idling and starts to misfire if i get rpm's above 1,00-1500 it stumbles for a bit then smooths out.  I have changed the coil, plugs and wires.  Any suggestions??

Answer
yes, i have an answer but not a good one. this engine in 2004-2005 were very common for this concern. the problem your having is that one of the valves in the cylinder head has pounded the valve seat into the head causing a poor seal. when you bring the rpm's up you give the valve  by normal combustion pressure to seat the valve. the only repair is to replace the cylinder head. if you have any local garage perform a cylinder leakage test. they will be able to onfirm this but, i've seen it a thousand times. i'm pretty sure you can googl this and you may be able to find a forum or chat about it. should you repair it, when the cylinder head is removed, it is clearly visible what has happened. the technical service bulletin for this is
05-26-3. you can probably google that as well. good luck and take care. should need further help please write back... -b-