Today I was driving home from school and out of nowhere the truck began to surge. Im not getting any noises at all and the rear diff was serviced one week ago so i dont think it is the rearend. I neede help with this i can have my truck in the shop. Its been raining down here so my guess is that something thats not supposed to be wet got wet. The truck is a 5.4 with 133000 miles on it and i need help asap!

 

Also the truck has a new number 4 coil pack

 

If you're hardly giving it any throttle at all will it accelerate and drive smoothly? If so, there's a good chance it could be a MAF. Your school shop likely has a code reader, talk to your automotive teacher and ask if they could hook it up and see what's going on. Used MAF are pretty cheap, I had the exact same problem in my 4.2L V6.

MAF means Mass Air Flow sensor.

 

Right I know that lol. no it does it through acceleration but very slightly. It does not feel like it when my cop went out, its not quite as jerky. Where is the MAF by the way?

 

I'm honestly not sure where it is located on the 5.4L specifically haha... It should be around the air intake/under the air intake.

 

I believe all three of the f150 engines use the same air intake. but mine has 2 sensors, one riht behind the filter and another a few inches behind the filter box.

 

How many miles on the spark plugs, and what brand are they?

 

They should have about 33,000 miles on them. and i believe they are motorcraft if i remember correctly. Also I discoonected the battery and pulled the intake tube off to see if there was any water in there but it was dry. Im considering just having all the plugs and cops replaced.

 

check your cops. my truck did this and never put out a code. id change them all out. btw i would also clean ur maf which is in ur intake tube with electrical cleaner that you can buy from an auto parts store.

 

I already cleaned out the maf. I pulled a few of the plugs lastnight and the ends of them were coated in carbon and looked like they had never been changed so im going to start there. If that doesnt work i will replace the cops

 

Sounds like 133k on the plugs instead of 33k - are you simply assuming they were changed at 100k because that's what the maintenance schedule specifies? How many miles were on the truck when you bought it?

 

I wasnt assuming they were changed because I asked the previous owner and they said that she was fairly certain that the plugs ad been changed. There was 120,000 on the truck when i bought it.

 

The problem here is the accurate discription of the driveability fault.
The term serge has a different feel from a miss.
Serge is more likely to be associated with the EGR going open introducing exhaust back into the intake when accelerating or cruising. This will feel like sergeing where power is not lost in any one cylinder but just lowered to all cylinders in general making the power rough..
A miss or stumble can be a coil that missfires. This slows engine rpm on an instant basis in one cylinder where serge is more drawn out effect.
Good luck.

 

Surge is the wrong term i suppose. this morning i started it up and it idled extremely rough and i was having what sounded like a miss. Im replacing the plugs tonight because the bottoms of them are covered in carbon build up and the gaps were .010 off. If that doesnt work ill change coils. Also how do I check to see if the egr is clogged?

 

EGR:
If clogged closed it would not cause the surging but would set a 401 code.
The surge from EGR would be possible if the vacuum regulator controlling it were to stick open a small amount and allowing vacuum it to open it.
So you can have two or more different fault types from the EGR system when you drive.
To test for sticking open, just remove the hose on the EGR to see if the surge is gone.
To test for blockage, apply vacuum to the EGR while the motor is idleing. If the idle goes rough or stalls the passage is open enough.
Good luck.