KNOCK AND SHAKE, can't get any help from anyone!
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Junior Member
Joined: Apr 2012
Posts: 4
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KNOCK AND SHAKE, can't get any help from anyone!
I pasted this from another forum hoping that myself and the guy I got this from can get some help.
I have an '08 F150 5.4L 3V that has a horrible knock that I re-reproduce at will (and make go away).65000kms on truck.
1. Bring engine up to operating temp.
2. Light throttle tip-in bringing RPM's to (but no more than than) 1000rpm.
3. Release throttle (idles back down to ~500rpm).
4. KNOCK and VIOLENT VIBRATION occurs and rpm's drop to ~300rpm.
5. Apply throttle to bring rpm's ~ 1500rpm and release.
6. Knock and vibration gone. Engine purrs back at idle.
I can re-produce this 100% of the time. Now what I do when making parking lot maneuvers (<1200 rpm) is make sure I rev teh engine to at least 1500rpm and it won't invoke the horrible knock/vibration.
When this does occur the oil pressure gauge in the dash is rock steady. Although it could be not repsonding quikcly enough to show a short interval drop in oil pressure. Dealer measured pressure at operating temp to be 30-35 psi.
In addition to this, I also have a hesitation somewhere around 2nd gear. Not much, but noticable.
Cam phasor? VCT? Fuel sending unit module?
I would thought maybe EGR but it's my understadning these engines don't have one.
I have the exact same trouble as this guy. Seems to be on the driver's side and there is no loss of oil pressure. HELP!
I have an '08 F150 5.4L 3V that has a horrible knock that I re-reproduce at will (and make go away).65000kms on truck.
1. Bring engine up to operating temp.
2. Light throttle tip-in bringing RPM's to (but no more than than) 1000rpm.
3. Release throttle (idles back down to ~500rpm).
4. KNOCK and VIOLENT VIBRATION occurs and rpm's drop to ~300rpm.
5. Apply throttle to bring rpm's ~ 1500rpm and release.
6. Knock and vibration gone. Engine purrs back at idle.
I can re-produce this 100% of the time. Now what I do when making parking lot maneuvers (<1200 rpm) is make sure I rev teh engine to at least 1500rpm and it won't invoke the horrible knock/vibration.
When this does occur the oil pressure gauge in the dash is rock steady. Although it could be not repsonding quikcly enough to show a short interval drop in oil pressure. Dealer measured pressure at operating temp to be 30-35 psi.
In addition to this, I also have a hesitation somewhere around 2nd gear. Not much, but noticable.
Cam phasor? VCT? Fuel sending unit module?
I would thought maybe EGR but it's my understadning these engines don't have one.
I have the exact same trouble as this guy. Seems to be on the driver's side and there is no loss of oil pressure. HELP!
Technical Article Contributor
Joined: Apr 2009
Posts: 10,697
Likes: 14
From: In the fast lane from LA to Tokyo...
first off welcome to the forum!
how many miles and are there any codes?
easy inexpensive things to check clean replace.....
clean the maf with maf cleaner
clean the throttle body with throttle body cleaner
replace the fuel filter
check and or replace the fuel pump driver module.....its on the frame cross member in front of the spare under the truck....
use some fuel system cleaner like chevron techron
check out the "how to" section of the forum to perform any of these tasks.....click link>>>https://www.f150online.com/forums/articles-how-tos-119/
you also may want to diconnect the battery to reset the pcm....
after you do all those if its still acting up there are other more expensive possibilities...
take a visit to the dealer to reflash pcm
the vct's
fuel injectors
plugs/cops
cam position sensors
timing chain tensioners
compression test
how many miles and are there any codes?
easy inexpensive things to check clean replace.....
clean the maf with maf cleaner
clean the throttle body with throttle body cleaner
replace the fuel filter
check and or replace the fuel pump driver module.....its on the frame cross member in front of the spare under the truck....
use some fuel system cleaner like chevron techron
check out the "how to" section of the forum to perform any of these tasks.....click link>>>https://www.f150online.com/forums/articles-how-tos-119/
you also may want to diconnect the battery to reset the pcm....
after you do all those if its still acting up there are other more expensive possibilities...
take a visit to the dealer to reflash pcm
the vct's
fuel injectors
plugs/cops
cam position sensors
timing chain tensioners
compression test
Last edited by 88racing; Apr 26, 2012 at 05:47 PM.
Thread Starter
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Junior Member
Joined: Apr 2012
Posts: 4
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it has 65000kms, and there are no codes. Truck pulls very good and idles very smooth. Also cleaned the throttle body today and it still does it. I have a couple friends that have the same problem and have not found a fix.