F-150 Bucking Occassionally
01-29-2016, 09:15 AM
#11
Here is an article that I found
Vincent, Ford Senior Master Technician
Category: Ford
Satisfied Customers: 1450
Experience: 28 years as Tech.
Disconnect the vacuum line to the EGR valve and retry it.
Now we can not completely eliminate the problem, but we can reduce it considerably.
What that engine has, and always has had, is a little too much EGR flow.
Blocking off the EGR passage changes the flow, but the EGR position sensor tells the computer that there is some there and the computer acts accordingly, changing fuel flow, timing, etc.
But what we can do is reduce the flow and trick the computer.
The EVR (EGR valve regulator) is the solenoid that controls the EGR flow. If you trace the vacuum lines from the EGR valve you will see the EVR. It has a black plastic cap on top of it that is clipped in place, tightly. If you remove that cap (carefully) you will find a foam filter and a oriface. With the engine running, if you put your finger over the oriface, the engine will run rough. That is turning on the EGR valve. If you look at the oriface, you will notice that it has a hex shape to it. The oriface is adjustable. Turning it in (clockwise, if I remember correctly, it has been a while since I have had to do this) will reduce the EGR flow. This will take a little time to get right. Drive the truck, reducing EGR flow a little at a time, until it is where you would like it. But not enough to turn on the Check Engine Light.
A couple of other things that will help reduce the feeling.
Factory plugs that are gapped correctly.
Double check the ignition timing, it should be 10 degs before TDC with the spout conector disconnected. The spout connector is a small grey plug located near the distributor. Unplug it before setting the timing.
Clean the inside of the throttle body. Open it up and you will see that it is slugded up. A little Carb Cleaner and a old toothbrush will take care of that.
Make sure that the gasket that seals the throttle bod to the intake manifold is not leaking. It has a tendency of getting sucked in.
Vincent, Ford Senior Master Technician
Category: Ford
Satisfied Customers: 1450
Experience: 28 years as Tech.
Disconnect the vacuum line to the EGR valve and retry it.
Now we can not completely eliminate the problem, but we can reduce it considerably.
What that engine has, and always has had, is a little too much EGR flow.
Blocking off the EGR passage changes the flow, but the EGR position sensor tells the computer that there is some there and the computer acts accordingly, changing fuel flow, timing, etc.
But what we can do is reduce the flow and trick the computer.
The EVR (EGR valve regulator) is the solenoid that controls the EGR flow. If you trace the vacuum lines from the EGR valve you will see the EVR. It has a black plastic cap on top of it that is clipped in place, tightly. If you remove that cap (carefully) you will find a foam filter and a oriface. With the engine running, if you put your finger over the oriface, the engine will run rough. That is turning on the EGR valve. If you look at the oriface, you will notice that it has a hex shape to it. The oriface is adjustable. Turning it in (clockwise, if I remember correctly, it has been a while since I have had to do this) will reduce the EGR flow. This will take a little time to get right. Drive the truck, reducing EGR flow a little at a time, until it is where you would like it. But not enough to turn on the Check Engine Light.
A couple of other things that will help reduce the feeling.
Factory plugs that are gapped correctly.
Double check the ignition timing, it should be 10 degs before TDC with the spout conector disconnected. The spout connector is a small grey plug located near the distributor. Unplug it before setting the timing.
Clean the inside of the throttle body. Open it up and you will see that it is slugded up. A little Carb Cleaner and a old toothbrush will take care of that.
Make sure that the gasket that seals the throttle bod to the intake manifold is not leaking. It has a tendency of getting sucked in.
01-30-2016, 09:06 PM
#12
Wow that's some crazy info with the EGR!
Well, changed distributor today. Easier than I thought. I had anxiety doing it. Had the timing right on 10 as well. Drove it around for a while and didn't get the bucking or hesitation at 30 and 45MPH. I'll drive it around more tomorrow and make sure the engine is running for a while and nice and warm.
I get it when I'm driving around a lot and then slow down to like 20/25 and then slowly go back to 30. I'll get it right there. I'll ease off and step on gas again. Then again on 45/48mph. Same thing. Today I went into a freeway (that's when I get it as well, slow into a cloverleaf, then step on gas at around 20MPG and right around 30 I get it.
But this time, nada, none of that. So far so good!!
I got mine on Amazon, same brand as one I would have gotten from RockAuto but I do like that free shipping from Amazon. And no stock fees when returning something.
Well, changed distributor today. Easier than I thought. I had anxiety doing it. Had the timing right on 10 as well. Drove it around for a while and didn't get the bucking or hesitation at 30 and 45MPH. I'll drive it around more tomorrow and make sure the engine is running for a while and nice and warm.
I get it when I'm driving around a lot and then slow down to like 20/25 and then slowly go back to 30. I'll get it right there. I'll ease off and step on gas again. Then again on 45/48mph. Same thing. Today I went into a freeway (that's when I get it as well, slow into a cloverleaf, then step on gas at around 20MPG and right around 30 I get it.
But this time, nada, none of that. So far so good!!
I got mine on Amazon, same brand as one I would have gotten from RockAuto but I do like that free shipping from Amazon. And no stock fees when returning something.
01-31-2016, 02:08 PM
#13
Wow that's some crazy info with the EGR!
Well, changed distributor today. Easier than I thought. I had anxiety doing it. Had the timing right on 10 as well. Drove it around for a while and didn't get the bucking or hesitation at 30 and 45MPH. I'll drive it around more tomorrow and make sure the engine is running for a while and nice and warm.
I get it when I'm driving around a lot and then slow down to like 20/25 and then slowly go back to 30. I'll get it right there. I'll ease off and step on gas again. Then again on 45/48mph. Same thing. Today I went into a freeway (that's when I get it as well, slow into a cloverleaf, then step on gas at around 20MPG and right around 30 I get it.
But this time, nada, none of that. So far so good!!
I got mine on Amazon, same brand as one I would have gotten from RockAuto but I do like that free shipping from Amazon. And no stock fees when returning something.
Well, changed distributor today. Easier than I thought. I had anxiety doing it. Had the timing right on 10 as well. Drove it around for a while and didn't get the bucking or hesitation at 30 and 45MPH. I'll drive it around more tomorrow and make sure the engine is running for a while and nice and warm.
I get it when I'm driving around a lot and then slow down to like 20/25 and then slowly go back to 30. I'll get it right there. I'll ease off and step on gas again. Then again on 45/48mph. Same thing. Today I went into a freeway (that's when I get it as well, slow into a cloverleaf, then step on gas at around 20MPG and right around 30 I get it.
But this time, nada, none of that. So far so good!!
I got mine on Amazon, same brand as one I would have gotten from RockAuto but I do like that free shipping from Amazon. And no stock fees when returning something.
01-31-2016, 02:45 PM
#14