i have a 05 in my shop automatic, start the truck up runs fine at idle,once in a great while you hear a almost miss in it while idleing, if you push on the throttle pedal and run it to say 1500 rpm and leave off the throttle it stays at 1500rpm, if you hit the throttle and leave off and the rpms go to 3000 rpm when you hit it, it will stay at 3000rpm till you shut it off, start it back up and it is back to idle,doesnt do it in gear only in neutral, truck does not smoke, does get good fuel milage, i thought injector but not making sence if it only does it in neutral,i hooked my scanner to it, no codes, when i check the throttle percentage and volts they go up and down with the pedal and show 0% throttle while its still hanging at the point you left off the gas, any one have this issue ever hate to go digging and replacing parts it doesnt need if anyone here had the issue or a way to figure out which way i should be heading with it, any help will be greatly appreciated

 

is it just the tach sticking at that rpm or does the truck really rev that high and stay there could be a bad
throttle position sensor.

 

no the rpms are there the motor is at 1500 and stays there,i thought throttle positioning sensor but it only does it in park or neutral,not when in gear, with the scanner hooked up it says the throttle is not being pushed and the ohm reading goes up and down with the throttle being pushed along with the % of throttle on my scanner goes up and down with it, just odd,if it did it in gear id be leaning towards that but not, once in a great while in neutral or park if you touch the gas it seems to be like its cammed up not all the time but sometimes, thats why i am leaning towards injectors, tough call when the parts to replace are not cheap

 

This sounds like a FCA issue. What are your rail pressures? What RP is requested and what is being delivered? That's where you need to check.