A buddy at work has a Ford Ranger with a 4.0 V-6 ( he has'nt grown up yet)., It's jerking and loosing power and showing CES. I hooked up my 9100 to pull a code (thanks Mike). And it shows P0320 which is a lose of engine speed to the computer. I looked at his engine and figured out that on the 4.0 there is a sensor at the inside of the crank pulley that sits over a splined section of the pully hub. It looks just like a sensor for an ABS system. We pulled the connection apart and cleaned it with contact cleaner and also sprayed down the sensor itself and it appears now that it seems to be running at lot better. My question is; Is this a recurring problem with the 4.0 and would it just be better to go ahead and spend the 33 Dollars and replace it? or is there something else we need to look at? Thanks

 

Graphing the waveform of the CKP would be a good start.

Make sure there aren't any sources of outside electronic interference around, cables for CB radios, stuff like that.

Verify circuit integrity from the PCM to the CKP. Disconnect the PCM and check resistance from pins 21 and 22 at the PCM to the pins on the CKP connector. I checked for any relevant TSBs and haven't found none. I don't do much drivability, but I don't recall the toothed wheel or the crank sensor as being problem areas in the 4.0. This is the SOHC engine, right? Make sure you have clean, solid connections at the crank sensor, drive it around a bit, see if it acts up again.

 

Well he reports that it seems to have helped since it does'nt do it anymore . I guess we hit it on the nose with the connector cleaning. I just suggested to him to get one and stick it in his glove box . that way if does go he has it there and 2 bolts and he on the road again. Thanks