My truck: 07 F150 FX4 SCREW with 77K miles.

When I'm driving between 40 and 50 MPH there's a spot where if I'm lightly giving it gas, the tranny goes into this weird BUMP, BUMP. It feels like the tranny does not know what gear to go into, so it's trying to find a spot. FYI, when I put it into O/D it does not do it.

I took it to the dealer, they checked it out, by the computer, and said they didn't see anything wrong. In their words, no computer errors. I'm going to take it into my mechanic that I trust, but he doesn't have time till next week to look at it.

I read online that some are saying it could be the spark plugs, but of course the plugs are a pain in the *** to replace.

So I was seeing if anyone else has experienced this and/ or might know what this is.
Like I said it only doesn't in between 40 and 50 MPH when just holding the pedal slightly down.
It's driving me crazy.

Thanks

 

That's a low grade misfire. Spark plugs and/or coils.

 

S#it, that's what I thought. Not a fun or cheap fix with those POS plugs. My mechanic said it could cost between $200 to $500 to do including parts.
Stupid design.

 

At 77K, they should have done been changed.

 

If a Scanner is used too look in the right place, it will show the cylinder with the faulty coil.
lack of knowledge is a wonderful thing to make extras money by.
Good luck.

 

2 things.
I looked at the trucks service records, that I have, with all records showing the service being done at a Ford dealership. While looking through, there is no notice of the plugs getting replaced. So I think it's safe to say, they have never been replaced.

As mentioned above, what is this "scanner" and what is its name. I want information before heading over to my mechanic next week. He's a great mechanic, but I would like to ask him about this "scanner".
He showed me the plug extracting tool if the plug breaks, which there is a good chance of. So he's not going to try and Mickey Mouse a broken plug out, but more knowledge goes a long way.

Thanks

 

OBD2 diagnostic scanner/computer.

 

Oh ok, I thought it might be something else.
Supposedly that is what the Ford dealership mechanic used to see if there was anything wrong, but he said he didn't see any errors. But I'm still not convinced they even tried.

 

Obviously all they did was look at stored data. It has to be DRIVEN with the scanner hooked up and watched in real time.

The local Ford dealer here will send a tech and a handheld scanner out for a ridealong when a customer complains of issues like this.

 

Running the misfire down in the absence of a code requires the use of a good scanner to look at the record of stored data for cylinder misfire kept for each cylinder.
The cylinder with the high counts is most likely to have a faulty coil.
The other way to detect the misfire in real time is to use a Scanner with a trap feature that triggers on the misfire and freezes the data exposing the cylinder that caused it.
Many shops are not knowledgeable about using all the ability they should have and just depend on codes.
Good luck.

 

Thank you for this information, helps me better to understand.
I would do it myself but I know I will end up stripping the broken plug and then I'll be SOL.

 

Just to be sure, it's not a spark plug issue but a coil issue.
Good luck.

 

By the way the double shift as you put it is not what is happening.
There are two levels of reaction.
1. The cylinder with the faulty coil multiple misfires.
2 The computer could actually stop processing for short instants in time.
When this happened there is no spark or fuel and the stumble get a bit violent to the feel.
Good luck.

 

I took my truck into my mechanic today and we went out on a test drive. I was able to get the truck to do the bumping and he said that is not the spark plugs or coil.
Went back to his shop and before he put it on his machine, he said it's the transmission having a problem going into the over drive gear and the transmission needs work. He then put it on his OBD machine and there was no misfires or any errors.
I told him I have the Ford ESP warranty that allows me to use my own shop for repairs, which he told me it would be better for me to go to a Ford dealer to do the repair. He said because Ford's ESP warranty people are hard to deal with and they want independent shop to jump through hoops and completely break down a transmission to find out what the exact problem is before they will ok a fix. He also said he would probably have my truck for at lease a month before I could get it back because of the warranty process.
If I was to go to a dealer, the warranty people will ok a new transmission right away no questions asked.

So after I was done talking to my mechanic, I took my truck to the dealer and had a mechanic ride with me, which he agreed it was the transmission. I have an appointment Tuesday to drop it off so they can do another test drive and give me a time line on the repairs.
Lets see what happens next.

 

Update!

We'll I took my truck to the Ford dealer the other day and today I got a call back from them regarding the shifting "bumping" issue.
What he told me was, the mechanic took it out and was able to get it to replicate the "bumping". He also hooked it up to a machine while driving and the machine registered a misfire. Opened it up and noticed 2 spark plugs were cracked and maybe a bad coil.
Right now they're replacing the plugs and coils, $600 OTD, and tomorrow I will be putting the truck through some test to make sure it is fixed.
$600 is not to bad I guess from a Ford dealership, since my mechanic was going to charge $100 per plug.

I got to make sure my truck is running good so it can pull my boat, since fishing season is about a month and a half away.