Very Weird issue
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Very Weird issue
<hr style="color:#DDDDDD; background-color:#DDDDDD" size="1"> So my trucks been doing something weird. When accelerating around 45-55 mph, a couple seconds after it shifts to 3rd, it does a weird type
Of shake/shudder. Feels like I hit a small bump in the road. Also when coming out of a cruise to accelerate, it will Make a very violent clunk and then speed up. I'm thinking it's a problem with my torque converter but my mechanic says transmission and my buddy says rear end lol. I dropped the pan and there was some shavings but nothing huge and it was the first time it was ever dropped. After 90k miles. Anybody got any theories? Any help greatly appreciated
Of shake/shudder. Feels like I hit a small bump in the road. Also when coming out of a cruise to accelerate, it will Make a very violent clunk and then speed up. I'm thinking it's a problem with my torque converter but my mechanic says transmission and my buddy says rear end lol. I dropped the pan and there was some shavings but nothing huge and it was the first time it was ever dropped. After 90k miles. Anybody got any theories? Any help greatly appreciated
Junior User
Joined: Mar 2009
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From: Crystal City, Mo.
Weird question calls for a wierd answer. My 03 Screw did the shudder thing when it had a coil pack going out. It never did do the other thing yours is doing but for some reason whenever the motor shifted it shuddered. My theory is that it wasnt as noticable at higher RPM's that the coil pack was going.
Good luck
Good luck
Junior User
Joined: Sep 2005
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From: Toledo, Ohio
Sounds pretty darn similar to the problem I just had on mine. It would start to shake or shudder around 45 mph. It was most noticeable under light acceleration. It turned out it was my #5 cylinder coil. Have your coils tested. Might be a low output coil. Im sure other wills chime in with ideas.
Lead Driver
Joined: Sep 2006
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It's one coil with shorted turns.
This trouble does not set a code.
Which one is the trick to find out.
The reason it acts the way it does in complex.
Not suprised your shops don't know about this type issue.
It's nothing to do with the transmission.
Good luck.
This trouble does not set a code.
Which one is the trick to find out.
The reason it acts the way it does in complex.
Not suprised your shops don't know about this type issue.
It's nothing to do with the transmission.
Good luck.
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Lead Driver
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Matt, if it was easy I would have said.
No code to tell you which cylinder it is but under the specific driving conditions it shows up, then goes away.
One way is to get a good scanner and set it up to trap the fault when it happens then it locks in the cylinder that caused the fault, in the readout data..
Good luck.
No code to tell you which cylinder it is but under the specific driving conditions it shows up, then goes away.
One way is to get a good scanner and set it up to trap the fault when it happens then it locks in the cylinder that caused the fault, in the readout data..
Good luck.
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So I've been messing with it today and noticed a couple things. It doesn't do the "shudder" when overdrive is off and it gets worse as the truck warms up. What would that indicate?
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Lead Driver
Joined: Sep 2006
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It indicates that when your out of OD, the engine control conditions change that causes the stumble.
Namely the EGR system is not in play when the OD is off, the RPM is higher and throttle application is not within the same range.
This changes the air/fuel ratio, fuel injection amount and ignition timeing.
When you switch off OD the A/F ratio come back richer again so the faulty coil can fire the cylinder because it requires 'less' voltage from a coil with shorted turns in it's winding.
The missfire record is cancelled so no CEL or code is generated.
It's a coil that is causing the problem.
It likely sounds strange to you but this is computer control and is the way it works.
Good luck.
Namely the EGR system is not in play when the OD is off, the RPM is higher and throttle application is not within the same range.
This changes the air/fuel ratio, fuel injection amount and ignition timeing.
When you switch off OD the A/F ratio come back richer again so the faulty coil can fire the cylinder because it requires 'less' voltage from a coil with shorted turns in it's winding.
The missfire record is cancelled so no CEL or code is generated.
It's a coil that is causing the problem.
It likely sounds strange to you but this is computer control and is the way it works.
Good luck.
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The truck would upshift, the motor is then underload and when I would accelerate, I would get that sputter. My dashboard would even crackle.
I changed my spark plugs, wich were WAY over due and also the plug wires. NGK ones. All for 100$ and a few sents.
To check wich coil, you could park in a dark spot or wait at night. Then look under the hood to see if a coil is shorting on the motor. You should see some small sparks. This will cause a ruff idle.
When changing plugs, put a bit of antiseize on the threads and make sure to gap the plugs correctly.
Lead Driver
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In some extreme cases, a coil can cause interferece back to the PCM and actually cause it to 'stop' processing anything as if you turned the key off and back on, until the program recovered again .
The shorted turns I refer to is not a short to jump spark to the outside to be seen under a dark viewing but a change in magnetic field produced around the coil core that causes 'lowered' output..
This condition might even be heard on an AM radio as a ticking noise between station tuning or on low received stations..
Good luck.
The shorted turns I refer to is not a short to jump spark to the outside to be seen under a dark viewing but a change in magnetic field produced around the coil core that causes 'lowered' output..
This condition might even be heard on an AM radio as a ticking noise between station tuning or on low received stations..
Good luck.
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Joined: Mar 2009
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From: Crystal City, Mo.
So is it fixed? Just curious. sorry for my absence. If ya gotta guess, try the one closest to the firewall on the passenger side. It seems to always be the issue. dont know if it is subject to more heat or moisture, but these tend to go bad. Just buy one and try it there. they are fairly cheap and easy to replace.
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I had a shudder in my 97 Expedition 4x2 with 4.6L at about 65,000 and 7-8 years old. Happened when torque converter lock-up occurred. I had never serviced the transmission so went in for a fluid flush and problem solved.
Also, Ford trucks and SUV's are famous for binding u-joints. Had a 98 Explorer 4x4 that began to shutter when approaching freeway speeds. Turns out it was bad u-joints.
I know most posts here are looking at engine problems, but in both my cases it was in the drive train.
Also, Ford trucks and SUV's are famous for binding u-joints. Had a 98 Explorer 4x4 that began to shutter when approaching freeway speeds. Turns out it was bad u-joints.
I know most posts here are looking at engine problems, but in both my cases it was in the drive train.
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i have troubleshot this all night. i bought one coil pack and changed one at a time. the problem is still there. i changed the plugs around 90,000 miles. it was doing it before and after. i just put a 6 inch lift and same tires just heavier and it does it even harder. still around 45-50 mph. it feels like my truck is about to fall apart. please help.
Lead Driver
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You may have more than one faulty coil.
At this time you really don't know what you have for good coils.
The reason the stumble occurrs in that speed range is the EGR opens and leans the mixture out so far as a normal condition, a coil or coils cannot fire the lean mixture so you feel it as a stumble until you do something with the throttle that causes either a down shift or added throttle that causes the EGR to close bringing back a richer mixture the coils can fire.
Try it that way and see what happens to prove it.
If the converter had an issue, the OD light would flash and there would be 700 series codes to be read.
Good luck.
At this time you really don't know what you have for good coils.
The reason the stumble occurrs in that speed range is the EGR opens and leans the mixture out so far as a normal condition, a coil or coils cannot fire the lean mixture so you feel it as a stumble until you do something with the throttle that causes either a down shift or added throttle that causes the EGR to close bringing back a richer mixture the coils can fire.
Try it that way and see what happens to prove it.
If the converter had an issue, the OD light would flash and there would be 700 series codes to be read.
Good luck.
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