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misfire when warm not when cold

14K views 25 replies 6 participants last post by  Elrond the hot rod 
#1 ·
I have an 2004 6.0 and ive dine head gaskets arp studs coolant filter oil cooler egr delete has sct livewire as well.. she has 155k and ive had rough running and a rough misfire.. ive noticed that it runs smother when oil temp is low, which makes me doubt stiction. After running a few contribution test and I get a few cylinders fairly low until I apply throttle, also I get stuttering upon locked up tq converter and light acceleration on the highway.. any suggestions before I go and buy new sticks thanks !!
 
#7 ·
What are some of the steps you have taken towards this. ? Have you replaced the injectors yet? Done a cylinder contribution/balance test ?
 
#4 ·
Ficm reads 48v steady occasional 47.5 for a few seconds not associated with the skip at all.. also ipr is pretty consistent with the icp icp preassures rise as they should.. if I detune the truck back to stock its pretty rough and white smoke at start up.. if I tune it and lift the idle about 100rpm it is much more manageable but still gets annoying on the highway and on the stop light
 
#9 ·
Next step will be some way of reading data and looking at the contribution test to see if you can narrow down twondering arroer is the problem.
Cylinder 7 is pretty low at idleeee once gas is applied it even outs 5 and 6 are sonewhat the same but not as drastic as 7.. im just wondering if it is a definitive injector issue ..
thabks again
 
#11 ·
i mean when its cold and i crank she fires right up like within 2 seconds of starter turning over... the more i use her the longer the cranks become, never a non start issue.

when i did the head gasket job i did take apart the spool valves and sand them lightly because the truck would miss and wobble like hell as it was cold before, now it seems to have reversed, could i have maybe sanded way too much ?

oil is super fresh maybe 600 miles motorcraft oil with motorcraft oil filter and fuel filters.,,

thanks again :thumb:
 
#13 ·
4 to 6 seconds of starter spinning the flywheel, would you try an additive like rev x or ar9100 ? or would you skip it all together.

i know most of the people that use that stuff have cold issues not really the reverse...

thanks :icon_ford:
 
#15 ·
meh im kinda scared of replacing one and straining it since these truck compensate one another to pick up slack from other injectors,
don't get me wrong i would much rather buy one injector than 8 lol,

Would that be your next step for the truck if it were yours?

Buy 8 new sticks?
 
#16 ·
No, I would just do the one. But that's me.

I've replaced two in mine, and it's been ticking along just fine since.

Since you had some missing on two others, you could kinda justify it. But a lot of times those are false miss readings.

Labor is free if you do it, so if you have to go back in so be it.
 
#17 ·
one injector locally is about $200.00 all 8 through warren would be $800.00, ima call him and see if he can sell one

i need to get my hands on my own pc so i can run tests myself.. this whole going to shop to nag on someone is getting old
 
#19 ·
How tight did you get the bolt on the spool valve coils? I polished a set of spool valves for a buddy and had the same problems you are describing. I went back and loosened up the bolts on the coils and problem solved. It does not take much to torque them I used a 4mm on a driver and just barely snugged it with a drop of silicone on the nut to ensure it does not back out

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#22 ·
I woulis free pull them and loosen the bolts. The valve only if oves .017 so any distortion makes a difference.

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Ima give this a try since this is free.. I might as well do this to the whole bank see If i get any improvement
 
#25 ·
Hey I have an 05' doing the same thing, new injectors on new bulletproofing all the goods, not necessarily rough idle but def miss under load and more so after it's been running awhile, what is this so called spoil valve and nut you talk about? Anyway I can do this without a computer? And it has basically done this since the rebuild a year ago and is def about to drive me crazy!! Any help would be amazing!!!
 
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