08 5.4 vibration while heat is on
#1
04-14-2016, 08:50 AM
Join Date: Jul 2015
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08 5.4 vibration while heat is on
For the whole winter (past 15k km) i had a nasty vibration that i was hunting down.
My 08 f150 5.4 Lariat would have this nasty vibration when i stop at a traffic lights or stop signs. Also it would vibrate in park. No code no nothing, idle solid at 640-660, but i would vibrate.
By coincidence i might have found the cause but i need your help.
It was winter and my heat would be always on. And yesterday finally it got warm enough that i would turn it off.
On my lunch break i started the truck and it would vibrate like always but i pulled down the windows and turned the heat off. My truck would vibrate less. Went to grab a coffee and when i got back, i left the heat off and turned off the truck. After work i started the truck(heat off before start) and it was soo smooth like never before! At a traffic light i even had to check the rpm to see if my truck was running and had almost a tear roll down my face hahaha.
When i got home, i just started the heat for fun and boom nasty vibration in my seat and door. Turn it off less vibration. Start the truck with heat off no vibration whatsoever.
So what kind of problem am i looking at here?
So far:
New engine, spark plugs, cops, maf sensor, fpdm, new batterya few other things..
My 08 f150 5.4 Lariat would have this nasty vibration when i stop at a traffic lights or stop signs. Also it would vibrate in park. No code no nothing, idle solid at 640-660, but i would vibrate.
By coincidence i might have found the cause but i need your help.
It was winter and my heat would be always on. And yesterday finally it got warm enough that i would turn it off.
On my lunch break i started the truck and it would vibrate like always but i pulled down the windows and turned the heat off. My truck would vibrate less. Went to grab a coffee and when i got back, i left the heat off and turned off the truck. After work i started the truck(heat off before start) and it was soo smooth like never before! At a traffic light i even had to check the rpm to see if my truck was running and had almost a tear roll down my face hahaha.
When i got home, i just started the heat for fun and boom nasty vibration in my seat and door. Turn it off less vibration. Start the truck with heat off no vibration whatsoever.
So what kind of problem am i looking at here?
So far:
New engine, spark plugs, cops, maf sensor, fpdm, new batterya few other things..
#2
04-15-2016, 08:13 PM
Few possible things since you didn't cover all bases in your post. When you say heat on or off, literally powered off or just temp turned right down.. Any change with fan speed? (a part mouse nest in the cage type fan will shake the entire truck but will change with fan speed, and vibrate without the engine running)..
Is it in AC mode when heating, ie is the AC compressor engaging and it's the vibration. There are vacuum lines that control things like the blend door etc, but can't imagine any of them would leak enough to cause a rough idle plus if they did, you wouldn't be able to switch from say defrost to floor etc..
Is it in AC mode when heating, ie is the AC compressor engaging and it's the vibration. There are vacuum lines that control things like the blend door etc, but can't imagine any of them would leak enough to cause a rough idle plus if they did, you wouldn't be able to switch from say defrost to floor etc..