Hey, yesterday driving my truck it started to shutter then wouldn't ya know it check engine light. Truck sometimes runs fine since and other times it's not running on all 8 cylinders, last week I had the spark plugs replaced at my ford dealership. I brought it to them yesterday and the hooked up the computer and a code for the butterfly valve In the intake manifold came up, they will be looking at it Tomrrow but I'd like some input, is this normal for them to come lose, to do the plugs do they have to remove the intake manifold? Maybe the mechanic did something and is hiding it? Could it be something else making it not run in all 8, it only loses a cylinder when it's warm, drives and runs fine cold, any input would be awesome

 

2010 f150 4.6 v 8 sorry for not mentioning that

 

No, they don't mess with the intake when doing the plugs. If they have diagnosed it correctly, it's probably just a coincidence. However, it could be a cracked boot if they did not replace that.

 

Cracked boot? Like a boot on the intake? They will be looking at it tomorrow, I've seen some 4.6 mustangs with the butterfly valve getting loss, tighten it up and use lock tight and good as new, I'm not mechanically inclined so I bring my truck to a shop, or else I'd poke around and look myself

 

spark plug boot. They can get damaged removing and replacing

 

The boots are under the COP and slide down on top of each sparkplug. They get brittle and sometimes crack when messed with. This causes a cylinder spark miss which can appear to be something else. They are rubber, heat causes deterioration an they should be changed when plugs are changed.

 

Hmm they never mentioned that, something to look into tho, I hope they find the problem tomorrow, I hate when my toys don't work like they should

 

Still haven't found the problem, they said something about the emc or ecm something like that, starting to get very very fed up with this truck, 120000 km and have had problems since day 1