Stumble At Idle

[7SEC1K]

95 dually 6.5 turbo diesel runs great most of the time but every once in a while it will pick up a stumble at idle when i apply the pedal it goes away and then returns when at idle again eventually it stops doing it and it happens only now and then what might this be thanks:confused:

[joe ball]

same problem everything new except lift pump starts real well runs great stalls just off idle ease on the foot feed bucks and stalls pull out of a driveway ease on same thing new ip,optical sensor and pmd.truck runs great at all other speeds oh yeah new fuel solinoid as well.

[bbtlr3]

Had a similar issue. It ran and started fine but developed a miss at idle. For me it was a bad injector. I pulled the injectors and had them tested. None showed to be way out of spec but 2 were getting really close according to the injector shop. I bought a new set and installed them and problem fixed. Hope this helps

[Robyn]

Always check the fuel flow to the engine to be sure things are working fine.
If the lift pump is not working properly then this could happen but is usually more noticeable at speed.

Open the fuel filter drain line up front with the engine idleing and see if fuel comes out. You should get a nice little stream of fuel. If no fuel comes out and the engine dies then Bingo bad lift pump or realted controls.

This issue could be related to a problem with the optical sensor in the IP.
Check the easy stuff first.

Make sure the battery conections are good and that you have 14.2+ volts at both batteries while the truck is running.

Make sure the ground cables are all good. Check the engine grounds at the RH rear of the intake manifold too to be sure they are in good shape and the connectionis clean and tight.

electrical issues such as these can and does cause issues.

Another little gremlin can be the filter harness on the IP.
This is a short little wiring harness with a little black box in the middle that plugs into the main engine harness and then into the very top of the IP (thisis hidden somewhat under the air plenum) A problem with this device usually causes troubles more at running speed but anything is possible.

Now if this is just a miss, you may have a bad injector.

If these have a metric buttload of miles on them I can almost gaurantee that they are on the skids.

Watch the tail pipe and if the little beast starts showing some smoke when its doing its stumbling thing then you definately have an issue.
Also make sure there are no codes showing (SES light on)

If there are no codes and there is the miss and you maybe see some smoke, I would yank the injectors and have them tested at a diesel pump shop to see whats up.

Good bet that a fresh set may just fix it, plus possibly add some mileage.

Hope this helps.

Robyn