[rrogers]

Hi I'am new to the forum,and have a problem with a 97' c/c dually that I just bought. When the truck is first started it runs rough
for about 5 -10 seconds then idles smooth.once you start driving
it runs fine until you come to a stop and it runs rough 5-10 seconds
then idles smooth again. I have changed the fuel filter and air filter
and no check engine light is on. the truck seems to run fine otherwise
just at idle it runs rough.Thanks in advance for any information,it is greatly appreciated

 

[bbm180]

Mine is doing something similar. Mine runs smooth on start up and until it warms up. After warm up the tach will move up and down slightly at idle. More of a change in the pitch of the motor sound than running rough though. Also if I keep the motor at about 1500 rpm and 30 mph I can hear the motor changing pitch. I recently changed my fuel filter too. Problem sounds similar to yours. Anybody have any ideas? Thanks

 

[centerline]

mine was doing the same thing. only did it when it was warm, and when I was driving easy thru the neighborhood I could feel it and hear it, as well as when it was setting in the driveway, kind of irritating. I just changed the ICP sensor in the front of the drivers side head and it cured my problem. it also cured other problems as well, it was dropping below idle when comeing to a stop and then picking back up to normal idle speed, and it had slow throttle response, and it was getting poor milage. you can test it by unplugging it while running. it may surge big once, but then stop doing the uneven idle, and then if you plug it back in, in about 45-60 seconds it will start doing the rough idle again. ICP sensor, 120.00 @ international

 

[bbm180]

Ok I'll check to see if I can find the sensor. This truck is new to me so I don't know much about it. Anyone happen to have a pic. of it so I know what I am looking for. And, is this the first thing I should try? If there is a good chance that this is the problem I don't mind spending the $120. Thanks for the reply.

 

[rrogers]

Last night I cleaned the regulator screen and it seemed to help
the problem temporarly ,but now it seems to be a little worse.Is it possible that I damaged the o-ring when I put it back together,and
maybe its getting air.Also is it possible that the flywheel is causing
the rough idle. It seems to be making alot of noise.I will try the IPC sensor tonight when I get home. Thanks for the information.

 

[radarman]

[ QUOTE ]
Last night I cleaned the regulator screen and it seemed to help
the problem temporarly ,but now it seems to be a little worse.Is it possible that I damaged the o-ring when I put it back together,and
maybe its getting air.Also is it possible that the flywheel is causing
the rough idle. It seems to be making alot of noise.I will try the IPC sensor tonight when I get home. Thanks for the information.

[/ QUOTE ]

Yes it is entirely possible that the flywheel is causing problems. Take the inspection cover off and see if you seen any broken parts. The flywheel will have about 1" of play in it, but much more than that is probably too much.

I would also check the oil. The powerstroke is very sensitive to oil. When the oil starts getting old, you can tell because it will start running rough at idle.

Good luck!