Hey guys I have an issue that was acting up awhile ago and it kind of just went away and had not come but until 11-8-15. While driving on the highway I noticed the truck would almost if you want to call it blurp. Just like you took your foot off the pedal than hit it again. it would do that once or twice than stop than a few more miles it would happen but only once than it didn't happen again until i was heading home. but it only happened once on the way home. its like the engine is running, running, running, off, running, running, off, running. You actually feel the decel but it happens so fast its not like the truck is loosing any real speed. but you can feel it if your driving it. I changed the fuel filter thinking maybe it was starving the engine of fuel than it would get a pocket of air and than regain the fuel. im thinking maybe fuel pump? starting to crap out? I just hope this is nothing big. If anyone needs a better explanation i will try my best. now it happened about 3 times since than. it almost feels like your running down the road than someone pulls on your bumper for a split second and than lets go. now heres another thing. the other day i ran a contribution test on the truck and cylinder 3 and 8 have a balance fault. i also ran an injector buzz test and that passed. there are no codes or anything thats why im thinking maybe fuel pump.

thank you,
AJ

 

Do you have gauges? If you don't can you hook up a mechanical gauge to the post filter port on the fuel bowl?

It could be the fuel pump; however, there is a reasonably substantial amount of fuel in the heads and you'll start to have a pronounced miss as you run out of fuel as the front injectors start to be the first ones that are starved...unless you are going down a steep hill.

Does this happen in the same location(s) or at the same time of day?

3 and 8 are the most common to fail the contribution test...and based upon my trial and error it can be dependent upon which tune you happen to be running when the test is conducted.

 

Cylinder 8 will almost always fail a contribution test unless you have an original, black CMP installed. Cylinder 3 will sometimes fail as well. Speaking of the CMP, the symptoms you have do kind of sound like yours may be failing . . .

 

Probably not the fuel pump.
Possible items to check:

1. Cam sensor and/or connection
2. IPR wiring harness for damage
3. TPS/IVS assembly for dirt or loose connections.

 

Above suggestions are gold, the most likely scenarios. And agreed, 3 & 8 often show bad on a CCT test. If curious there are lots of threads on the subject.

But if you get through all that and still have the problem try a new ignition switch, pic below. Mine had a very intermittent outage of power to the PCM. Gradually got worse, from an instant off to a really long, seat puckering second and a half.

 

I do have gauges but nothing for the fuel. this does not happen at the same time or location or the frequency of it either. its just very random

 

I did not have a black cps installed it was actually grey. now i did have one in my glove box that i bought from the dealer once i purchased the truck after reading a few posts to keep one on hand. the color was like a blue purple. I installed it and it went away but this morning she was really acting up. If you keep the pedal steady it kind of surges and than it will get better and it only happend a short period today than went away.

 

I tried the CPS with no luck.
Where is the IPR located? and im guessing thats injector pressure regulator?
and the TPS is the throttle position sensor? and what is IVS

 

Idle Validation Switch. It's part of the pedal assembly. Works kind of like a brake light switch to tell the PCM that the pedal is depressed. I don't think it's something you can buy seperate like the TPS, but it's easy to fix if its not making contact properly.

 

Found a pic of the IPR (and everything else) for ya.
https://www.ford-trucks.com/forums/1...pr-sensor.html

 

Is there a write up on how to correct the IVS? And after doing some more research. I'm truly leaning towards the TPS/IVS

 

Unsure if a dp tuner setup requires the removal of the pcm.


My TS6 did and I didn't snug the firewall bolt up tight enough and had the exact same problem.


Was intermittent at first and then viral to the point of tow.


When I got to the shop destination, just by chance I was doing the wiggle test on everything, and when I got to the under dash side I bumped my pcm with my elbow and the truck shut down. Whallah!!!!!!!!!!!


Couple of threads later in here, I torqued it to spec and she and I just haven't looked back.




Never know?!


Denny

 

Hey guys I have another thread going but I will post on here what i have found. After doing some research I had an extra CPS in my glove box and decided to throw that in. I swapped them out and the truck acted up a day after installing it but after that the problem has gone away. I did buy a TPS but its sitting in my truck waiting to be installed but im not sure if I should even replace the TPS at all

 

Wait and see, but if it did it once since the new CPS, it will probably rear it's ugly head again in not too long.

 

I wonder, when the truck cuts out, are you just losing engine power or do you lose electrical power also? Any weird lights or gauge activity?