Well I wanted to give an update, we replaced the fuel pump assembly and the fuel pressure is lower, on running is at 66. However, when the engine is idle, or in Drive and stationary the engine is still not running smooth. I have someone that helps me with this project, he checked the hoses and spark plugs again, the coils and could not find anything wrong. There is no check engine on the dash board. I can drive it but it is just not running smooth like it did before the tune up.
I’d do a compression test. Dry and wet.
I had a dealer check the schematics based on the VIN number and they said the pressure should be around 55 running. They directed me to check for a fuel pressure control module or fuel pressure driver module.
I don’t think your rough idle problem is related to fuel pressure
I might be wrong, but that’s my opinion, based on what you’ve told us up until now
To further clarify, I don’t even think you have a fuel pressure problem
Rough running near idle rpm, if it isn’t a vacuum leak, and the fuel pressure isn’t the cause, then my next guess would be dirty injectors. If one or more is a little bit clogged, it’s much harder for the injection system to meter out a little fuel (like for idling) than a lot of fuel (like for driving on the freeway). When idling w/slightly clogged injectors you don’t get the same amount of fuel into all the cylinders, and the computer isn’t able to tell which cylinder is causing the problem in order to correct.
You might try a dose of injector cleaner in the fuel tank, like techron or similar. Even if it doesn’t do much, if it does anything to help you know you may be on the right track.
I’m thinking it might be a secondary ignition problem
In spite of the fact that it’s been stated there’s no problem as far as that goes
Food for thought . . .
I’ve seen lots of bad plugs, wires, boots, etc. that cause a misfire and do not set a code, and do not turn on the check engine light
If you drop a new plug, it might be working sufficiently well to not set a code or turn on the mil, but the engine will be running poorly
I’m wondering if anybody has carefully examined the coils and boots. Ford COPs use a spring inside the boot. This spring commonly gets corroded, or literally comes unwound, causing rough running. Many times, this does not result in a code or a check engine light
Might also have bad pigtails for injectors(s) or coil(s) . . . seen that more than a few times
At this point after all the time and money has been spent I think it would be worthwhile to go back a few steps and check the basics. You say you have someone helping you, is this a mechanic with a decent scan tool?
I would want to know what the short term and long term fuel trims are at idle and at 2500 rpm. I would want Mass Air Flow readings and BARO value. I would check to see which cylinders, if any, are misfiring at idle. I would want fuel pressure sensor values if present. On a late model car testing begins in the driver’s seat before the hood is opened and anything touched.
Personally, I don’t think fuel pressure has anything to do with the problem. If the vehicle was running at least halfway well before and only started this after the plugs and fuel filter was changed then you may need to consider how easily, or not, the coils were to remove.
This could be especially true if tugging them straight out was involved instead of some gentle twisting and whether or not there was any scale or corrosion in there. It’s not that difficult to damage a COP, plug wire, or what have you in the act of removing them if they’ve been in place a long time.
the person helping me is a mechanic and has a scanning tool. I will relate to him what you guys advised me to do and proceed further. He checked the coils and boots and found no problems. His logic is based on the fact that there was also an intermittent problem before changing the spark plugs and fuel filter. Climbing a hill the engine would seem to lose power even applying gas gradually. This always happened after traveling for a while on the freeway and always when climbing. At this point there would be a noise, like metal to metal coming from the front left wheel, I believe it was related to the 4x4 system losing vacuum and engaging the wheel. The noise stopped every time I would take my foot of the gas. If I would open up the throttle all the way the engine would rev up and get the power, no noise from the wheel. The truck was at the Ford dealer for a few days they did not hear the noise and could not figure out the problem. They suggested a tune up, so there I am 
Has the mechanic tried cleaning the MAF?
MAF was checked and also he checked the coils and tested each one with the computer plugged in. I will try the fuel pressure control module and if I cannot fix it this way i will take to a shop. Right now we cannot find the fuel pressure control module, it is supposed to be around the driver side rear wheel but we cannot see it.
I checked and 2 other people checked under the back of this vehicle and we cannot find the fuel pressure control module. I was told is part of the fuel pump assembly but when I call the dealer based on the VIN number they tell me I have a electronic control box that controls the fuel pump. They say is behind the spare tire or the RL tire but I cannot see it anywhere. On a F150 truck is mounted right under the frame.
With all due respect, why are you looking for that module?
The overwhelming majority of the people on this website are suggesting that your fuel pressure is . . . and was . . . normal, and that it doesn’t . . . and didn’t . . . have any role to play, in regards to your complaint
I’m still thinking it’s quite possible you have a secondary ignition problem
I agree with db above. Improper fuel pressure is pretty low on the list of things I would be checking for your complaint.
tank pressure and fuel rail pressure/temp sensor locations. You want fuel rail.
You can get the fuel rail pressure sensor separate from the rail
But that’s not the point
In my opinion, the point should be that OP needs to pay another mechanic for a proper diagnosis and repair
Because that idea with the fuel pump assembly didn’t work
And most of us had stated that, in our opinions, fuel pressure had nothing to do with his problem
With all due respect to people giving him ideas/help and OP, I think he’ll take anything we give him and hang himself with it . . . meaning he’ll pay a lot of money to install parts which will very likely not fix the problem
He should find another shop and say “My original complaint was such and such. Mechanic A installed such and such parts. Not only was the original complaint not resolved, but I’ve had these additional problems EVER SINCE. I would like to pay you to diagnose and repair the problems.”
Well thanks for the advice found the problem, cracked spark plug. Hairline crack barely visible. I had someone else look at the problem like suggested.
But I still have my original issue, when driving on freeway with engine reving arround 2600 there is a horible noise grinding coming from the front wheel. It is intermitent and only when climbing a hill. I was told it might be the 4x4 engaging but why does it stop when I take my foot off the gas and starts again when I give it gas. Initially I thought it was because I am towing but it happened even when not towing with lower revs. This is making me pull my hair out as nobody can give me an idea as to what to do. So far people here offered me very good advice so maybe someone can suggest something. Ford dealer could not replicate the noise and could not find a problem. This seems to happen only when driving on the freeway and after some time on the road.
“found the problem, cracked spark plug. Hairline crack barely visible.”
With all due respect . . . I TOLD YOU SO, A LONG TIME AGO
"I’ve seen lots of bad plugs, wires, boots, etc. that cause a misfire and do not set a code, and do not turn on the check engine light
If you drop a new plug, it might be working sufficiently well to not set a code or turn on the mil, but the engine will be running poorly"
Yup . . . I told you that on September 3rd
db4690 you were right but the dealer said the presure is too high at 66 so that is why I was pursuing that. Can you provide some insight about the initial problem withe the intermitent noise? I can take it to a shop but they will keep it for a day or so and then say they could not find anything. Any Tests OR COMPONENTS I SHOULD check? I am thinking about selling this Expedition be cause of this problem.
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