i own a 2004 Ford Ranger XLT Fx4 Level II
i recently changed the harmonic balance and the crankshaft position sensor. the engine light came on and the codes were that there was a mifire in the 1st and 5th cylinder and it says that it was detected in the first 1000 revolutions. any ideas why this is happening, thanks

 

Having the same problem with my 2004 Ranger. Changed the plugs, wires and coil pack, reset the computer and the check engine light still comes back on after about 50 miles.

 

Where did you purchase your Crank sensor?

Batman...do you have the same code as jhawton?

 

i purchased my harmonic balancer at carquest and my sensor at canadian tire... i dont know if that makes a difference

 

If that was the only changes you made, I would suspect them. Try a crank sensor from Ford.

 

I'm having issues on my 05 3.0 w/#3 being the suspect cylinder only,after some research and help from members in here, the heads seem to have issues from04-06years with the exhaust valveseats being the problem causing loss of compression. I have changed plugs and wires only to have the issue return like batman.
Neither one of u guys posted what size engine you have.

 

The first guy has a 4.0

 

i agree^^

what was the reason behind changing the crank sensor?
id suspect you bought a lemon sensor. buy a motorcraft for things like that.

 

yes it is a 4.0 and it is a BWD sensor. i replace it because when the harmonic balancer went , it wore into the sensor.

 

oh ok so it the harmonic went bad wore into the sensor and it threw those codes, then you replaced everything adn still got the same codes or new ones?

ya ive had trouble with there sensors before too. the IAC sensor they had.

i would try to return it. but deff try to get a motorcraft one.

 

i think the codes were from after but i think i will try a new sensor, probably a ford one first

 

i put on a new sensor from caquest it is an OE crankshaft position sensor... seems to have done the trick