I have a 08 F150 with the 4.6L. When I'm driving and doing about 60-70 MPH then their is a slight shutter. It will also do it when cruise control is engaged. Not sure where to look or look into. Anything will help, Thanks

 

There are a lot of reasons why your 2008 F150 with 4.6L engine might have a slight shutter between 60-70 MPH. It could be a bad spark plug, a bad fuel injector, dirty air filter, faulty MAP sensor, fuel system problem, or a vacuum leak, to name a few. I'd check for an OBD code first, although I doubt there will be one for such a minor issue. Have you noticed any other symptoms?

 

Haven’t noticed anything else besides the stutter. The spark plugs got replaced in December I believe. Then I just replaced the air filter.

 

?what model plugs, and what were they torqued to?

?were boots and springs replaced when plugs installed?

? have you had coolant leaks ?

 

not sure about the plugs, I had the dealer ship do it when I had them do a transmission flush.
I hade a coolant cap pop off on the back of the intake manifold but I fixed that.

 

you probably got coolant down in plug wells. If so, it is common to encounter misfires until you clean everything up and replace boots and springs.

Given this, plus fact that you don’t know what plugs were installed, if they were properly torqued, or if boots/springs were replaced with the plugs, that is where I would start if I were you.

good luck and please update thread as you go.

 

Coolant ,gas, heat,age kill boots ,replace all boots . You can buy good quality boots online cheaper . Clean high volt tabs on cops they corrode. Clean your wells out real good , don't let liquid and stuff get in there. Use a small amount of dielectric grease on each end of boot . It stops heat seizing and try's to keep moisture out of boot . vacuum and clean all wells . Boots may look okay but it only takes a pin hole to drive you nuts.
Blow away dirt before removing boots or plugs . Replace any connector cop/ injector not locking on , solder it in and heat shrink it . You can buy connectors online in sets cheaper.
When plugs are out it a good idea to try to remove built up carbon around snout area of plug in cly . Carb cleaner will melt it , that carbon is tough no additive or amount of heat will remove carbon . Be careful with carb cleaner it will flame . Diamonds are made out of carbon . you can put a torch on carbon ,it will turn white hot and glow .

 

I had the plugs replaced after the coolant incident but Ill take a look at the boots.

 

if they didn’t bill you for them, they weren’t replaced (especially at the stealer ship).

undertorquing and/or loose plugs is a known issue

it’s most of the same time/labor to replace the boots/springs and check torque as it is just ‘take a look at the boots’

 

Pulled cylinder 8 and 2 spark plug and boot. Cylinder 8 boot and spark plug looked fine as well as 2. Used a mirror and looked down in them looked fine as well.
The shudder goes away when I turn over drive off. I don't have it in low speeds. My plan of action rn is to drive it till I need to fill up again and see if it was I just got a bad batch of gas. Plan on either running a non ethanol batch or doing a higher octane.
I also looked over the engine and didn't notice anything out of the ordinary.