flutter at idle

[7.3turbodiesel]

My truck just recently flutters at idle. normally it would just stay at about 550rpm idling in park. But now it cycles every 5 to 15 seconds from 550 and jumps up to 650 0r 700 for a 2 seconds and then back down to 550. any ideas what is causing this?

 

[97powerstroker]

my truck seems to do this also,but mine only jumps up maybe 50 rpms,just enough to notice it,ive heard a bad icp sensor could be the issue,try unplugging while it idleing and see if it does it,if it does not,then you will need a new sensor.someone correct me if im wrong.

 

[Zookie400]

see if the revving/bogging coincides with the A/C compressor clutch coming on and off.

 

[hheynow]

My truck just recently flutters at idle. normally it would just stay at about 550rpm idling in park. But now it cycles every 5 to 15 seconds from 550 and jumps up to 650 0r 700 for a 2 seconds and then back down to 550. any ideas what is causing this?

Try starting it in park and see if the idle is smoother. I have a similar problem as when I start it in park I have the romps (Not me...my truck! ). The tach jumps from 500 to 1000 and the engine shakes until I rev it up then it settles to a smooth idle. When I start it in neutral I have a perfect smooth idle. My problem is a bad neutral safety switch.

 

[7.3turbodiesel]

where is that switch located on the truck?

 

[94f450sd]

where is that switch located on the truck?

drivers side of the transmission where the shift linkage is.dont forget if youre in cold weather the EBPV could also be closing if you guys still have it.this will cause the idle to raise a bit.

 

[hheynow]

Got the neutral safety switch from Ford but initially they sold me the wrong part even though I gave them the correct year and VIN. The F7TZ-7F293-AA has the wrong size connector and the pins are different than the correct part which is F5TP-7F293-AA which has a new numbered box SW-5063 (F5TZ-7A247-B)

 

[7.3turbodiesel]

what is the ebpv? where is it located?

 

[hheynow]

exhaust back pressure valve
Under the turbo you'll see a connecting rod. Where it connects to the left part of the turbo there is a butterfly flap (ebpv) inside that housing. During cold ambient starts a sensor closes the flap allowing faster warm up time. When you drive with it closed you hear a "woosh" hissing sound which is normal. Once the engine sensor senses engine heat the flap opens. During warm weather its always open. Many disconnect the connecting rod at the turbo's left side and use a wire to tie the flap to always open because it fails to operate properly.