miss or hesitation

[JFringer]

I have an 04 305hp 555 truck that has developed a miss or hesitation like symptom over the past couple of weeks. it is a 6 speed and when changing gears i let off the throttle to change gears and then go to hit the trottle again there is a little hiccup and a puff of black smoke and then it clears up and runs like champ. it almost acts like an old carburated gas engine when its cold. does not matter if the truck is cold or hot does it all the time. past few weeks it has done it off and on but now its all the time. truck has 230,xxx miles injectors changed at 190,xxx. truck is as stock as it gets. thank for any advice

 

[p-Bar]

Could be the FCA some guys have diagnosed with using 2 stroke oil in the tank as it lubricates the sticky FCA others say its not good to use 2 stroke oil .

 

[JFringer]

Would power service diesel additive work the same way?

 

[p-Bar]

Not sure on that . Have you been using that now?

 

[cerberusiam]

Would power service diesel additive work the same way?

Yes, the PS works well as a ongoing additive. You can overdose a tank of fuel to make it happen faster but it doesn't have much for cleansing properties. You could do the SeaFoam or CRC injector cleaning routine and that will hit the FCA also. Will maybe tell you if that is the problem.

 

[jgillott]

We were experiencing a mild case of symptoms similar to yours a while back. One strong dose of ashless 2-cycle engine oil did the trick. As mentioned, some people are dead set against it, but it worked well and no obvious lasting symptoms for us. If it clears it out for you, you may want to consider an additive of your choice for a while and see what happens. I personally use Powerservice since it is so readily available here.

 

[JFringer]

I put a 250 gallon dose in the tank yesterday and a whole bottle of Lucas fuel lubricant and it has stopped the problem so far. Knock on wood! The only thing that remains is when I tap the throttle to rev it up it comes down to 1000 rpm and hovers there kinda like a high idle. Any ideas on that?

 

[Joseph Donnelly]

Could also be the APPS. Check your odometer for DTC's.

 

[cerberusiam]

That is a typical 6 speed operation. If you just start to engage the clutch will it drop back to normal?

 

[JFringer]

Thanks for all the help. This thing is like a dang space ship with all it's electronics compared to my 93 12 valve