2001 screw 183k give or take, 4x4 auto 4r70w 5.4,355 ratio. Plugs changed with motorcraft about 5 thousand miles ago. Fuel filter changed about 15k miles ago no codes on dash, brakes are not dragging as it rolls in neutral, ac turned off, ambient air temp is 90 I noticed the hotter the days the worse it is. It will be up to temp had been running for an hour I go from a dead stop up a tiny incline and it shifts from first pretty ok then as soon as it hits 2nd it falls on its face I have to lay into it pretty good to get it to move once in high rpm around 2300 on up it pulls good. Has a Cai on it like I said no codes. Trans has been serviced and shifts fine don't slip don't miss shifts or jerk or hang around in high rpm it did feel weird once today but I had to push it to get on the interstate and the trans just quickly shifted from a revved out 2nd gear up to 3rd then OD quickly as I let out of the throttle. Holds 2 grand on the interstate ok but if I drop to 65 it dogs until I force the converter to unlock and regain speed. My question, what should i look for? I'm thinking clean the maf, maybe the throttle body, then scan for ghost codes or pending? I can see live data. What should I look for? Please help this site has helped me every time i post here I sure hope someone has an idea. Also when I turn on the ac it pulls it down even more...

 

Check your fuel pressure. Your fuel pump might be on it's way out.

 

I was scared to hear that. I'm waiting on it to cool down so i can clean the maf its not been cleaned as far as I know possibly ever.. I did take some photos of it running on a live data scab




the truck does not crank any longer than it should to start it fires right up zero rough idle it can sit for 2 days and starts up like a new one

 

From what I gather the statement b1s2 and other one are the o2 sensors saying I'm burning most of the fuel and seem to be within range. What about the others? I know I can't base much off some baseline numbers without graphing it throughout the entire rpm range I just was curious. I think I'm going to have to test the rail pressure as mentioned above and previously suggested I just have to rent or buy a fuel pressure tester.

 

Your Scanner is showing you the basic fault.
LTFT 1 and 2 are shifted rich 23% and 24% almost to the point of setting codes 171/174 at 25%.
Find the Vacuum leaks.
Until you, do expect hot stalling, low rpm rough running and poor gas mileage from running to Rich..
Good luck.

 

I had a lean code I found the egr tunes that run to the manifold broken I replaced and code went away but I guess I have a leak still that is somewhere high enough in the manifold to effect both banks. Maybe my pcv tube is **** and it needs replaced...it's dry and rotted as hell on the part that goes into the valve cover and I just found a leak behind the battery as well. It's effecting the blend door depending on throttle and load

 

The PCV elbow behind the intake also rots.

If you have a CAI with oiled filter, I bet the MAF is fouled.

 

I checked the pcv system it has zero cracks or holes from the back of the manifold to the valve itself and fits snug. I did have a busted line behind the battery that leads to the hva system through the firewall the previous owner had taped with a plastic ice maker line taped in to splice them together I fitted a hose and fixed that I then cleaned the maf the temp sensor while i was in there and sprayed and cleaned out the throttle while it was still in the truck then soaked it let it sit and fired it up after 10 min got a little smoke it cleared up and let it idle and took it for a drive. It runs good as of now and I hope I fixed the issue. Can't feel it miss at idle anymore where it would previously shake the truck enough for me to feel it and noone else and now other than a bad muffler seam I can't hear it running. I appreciate all the replies if I find anymore out ill post any updates. I hope it dont have a intake leak or injector o ring seep.

 

I have a 2004 FX4 SuperCrew, don't know how different they are from the 2001's, but if you have problems again, I'd just replace the MAF. Could also be the throttle body. My 2005 Super Duty had loss of power issues last year and the dealership installed a new one and problem was fixed. Sometimes the TP sensor on the throttle bodies go bad, also.

 

You may want to watch this video. It shows how to troubleshoot the vacuum line/system you are speaking of.

 

Sounds like a fuel problem. Have you ever changed your fuel filter?

 

Look again at the post you quoted...........

 

My bad