Vibration in gas pedal?

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brandoncw
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Vibration in gas pedal?

Post #1 by brandoncw » Thu Mar 08, 2018 8:51 pm

So i have noticed a strange and fairly strong vibration in the gas pedal when the engine gets a fairly heavy load at lower rpm (900- 1300) such as going up a steep hill. It kinda gives my foot a tingly feeling. I only feel the vibration in the gas pedal and just the usual engine vibration through the shift stick. Any ideas?
Last edited by brandoncw on Mon Mar 12, 2018 10:48 pm, edited 1 time in total.
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Daubee 1978
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Re: Vibration in gas pedal?

Post #2 by Daubee 1978 » Mon Mar 12, 2018 9:23 pm

I would guess your engine is missfiring under load. Trying doing a tuneup first.

brandoncw
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Re: Vibration in gas pedal?

Post #3 by brandoncw » Mon Mar 12, 2018 10:43 pm

Daubee 1978 wrote:I would guess your engine is missfiring under load. Trying doing a tuneup first.

My engine is very audible and i dont hear a single skip of a beat wich would be very noticeable at low rpm like that and i have basically put brand new everything on it. Runs great with plenty of power. Unless my ground comes loose. Turns out an engine runs like s*** with a loose ground.
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THE FRENCHTOWN FLYER
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Re: Vibration in gas pedal?

Post #4 by THE FRENCHTOWN FLYER » Tue Mar 13, 2018 12:05 pm

With everything being replaced maybe it is in the drivetrain, not the engine. Perhaps a bad U-joint, an out-of balance driveshaft, or a missing transmission vibration dampener. I once had an intermittent vibration caused by a bad wheel.
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brandoncw
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Re: Vibration in gas pedal?

Post #5 by brandoncw » Tue Mar 13, 2018 12:41 pm

THE FRENCHTOWN FLYER wrote:With everything being replaced maybe it is in the drivetrain, not the engine. Perhaps a bad U-joint, an out-of balance driveshaft, or a missing transmission vibration dampener. I once had an intermittent vibration caused by a bad wheel.

Its strange, you' probably have to drive it to know exactly what I'm talking about. It feels about like when you set your phone to vibrate and you get a call. I have been needing to swap to a one piece drive shaft because my two piece isn't working with the np435 trans that i put in place of the original m5od (the slave cylinder siezed and there was the np sitting in a truck out back). It keeps breaking my trans mount until i finally welded one together as a band-aid. Maybe that's where its coming from.
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Re: Vibration in gas pedal?

Post #6 by bubba22349 » Tue Mar 13, 2018 2:31 pm

brandoncw wrote:
THE FRENCHTOWN FLYER wrote:With everything being replaced maybe it is in the drivetrain, not the engine. Perhaps a bad U-joint, an out-of balance driveshaft, or a missing transmission vibration dampener. I once had an intermittent vibration caused by a bad wheel.

Its strange, you' probably have to drive it to know exactly what I'm talking about. It feels about like when you set your phone to vibrate and you get a call. I have been needing to swap to a one piece drive shaft because my two piece isn't working with the np435 trans that i put in place of the original m5od (the slave cylinder siezed and there was the np sitting in a truck out back). It keeps breaking my trans mount until i finally welded one together as a band-aid. Maybe that's where its coming from.


Yes that would be a strong possibility if your drive line angles aren't in spec. That's should be you first place to look then. Good luck :thumbup: :nod:
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brandoncw
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Re: Vibration in gas pedal?

Post #7 by brandoncw » Tue Mar 13, 2018 3:31 pm

bubba22349 wrote:
Yes that would be a strong possibility if your drive line angles aren't in spec. That's should be you first place to look then. Good luck :thumbup: :nod:

Ill try shimming the mount and carrier to see if it helps any
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Re: Vibration in gas pedal?

Post #8 by brandoncw » Fri Mar 16, 2018 10:41 am

I think my leaf springs are getting weak too causing some axle wrap. Gonna fab up some bars to help stabilize my rear end.

My theory behind this is when I'm in first or second taking off, the trans shudder rather violently and that would also be the time when the most torque is applied to the wheels.
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Re: Vibration in gas pedal?

Post #9 by 1986F150six » Thu Mar 22, 2018 2:26 pm

This is to be put in the "for whatever it's worth" category... sometime back, the oil pan needed to be removed from my 1986 4.9L. A mechanic friend did this for me and I was not with him. I know he lifted the engine enough to remove the pan. When I drove it, there was a pronounced vibration @ ~1250 RPMs. This occurred in any gear and was more pronounced as a load was applied. I checked transmission and engine mounts. I tried with and without the A/C on. It turned out that when the engine was lifted, the A/C hose which is mounted along the firewall was left in its retention clip. Apparently, the metal A/C lines were "tweaked" and once the engine was lowered into position and secured, normal engine vibration was transmitted through the hose which set up a resonance in the hood and firewall. Once the hose was adjusted, the annoying vibration disappeared!!! :oops:

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