Lose all low end power please help

[gschacke]

I got a 97 5.4 been having issues with low end power and miss i changed the upper and lower intake gasket along with plugs coils and injectors for the 2 cylinders missing issues still present but it got worse intake gasket was blown out any ways now I'm having a problem on top of the miss if the engine is cold or I shut it off for 15 mins roughly I can take off and accelerate ok still not perfect but after about 2 mins I lose all low end torque it starts shaking violently stumbles surging and matted to the floor can barley pull 2 grand it gets so bad even in 4low it can't even spin the tires fast enough to climb a wet muddy hill I have people telling me intake gasket and others saying the cats are bad can someone please point me in a direction the lower intake isn't cracked the imrc is working the expedition only has 116000 miles on it any help would be great

 

[DieselMonk]

What OBDII codes do you have? Did you get aftermarket replacements or OEM for the parts you changed?

 

[gschacke]

Only codes that pulled up was miss fire on 1and3 and those cylinders are missing at the same rate wat I mean is 1 miss then 3 miss they show they miss fire count is equal I have a oxygen sensor bank 1 sensor 1 heater problem and a code for egr system high input pressure or something like that I did find the fuel tank pressure sensor had a broken wire fixed it and that did help but still has the miss fire and at wot it's still stumbling and half throttle same thing at 1/4 throttle it's like surging it's like it's missing the clears up then back then clears up. As far as parts go injectors are ford injectors when I swapped them i pulled them from a used 5.4 with good injectors coils are napa brand coils and are working i cylinder swapped and the miss didn't move spark plugs are wat ever were the recommended plugs but I belive autolights I removed old muffler and that seemed to help I will add I have noticed I can't smash the throttle at take off it won't accelerate for squat and also noticed at idle at night dash lights head lights surge got brigh go dim ram surge when in gear by couple hundred ram like it's starting to run right then fight back to wat it was doing I APOLOGIZE FOR LONG MESSAGE BUT I SEE TO MANY POST WITH SHORT ANSWERS OR NOT THE ANSWER TO THE QUESTION SO TRYING TO GIVE ALL THE DETAILS FOR THE BEST HELP THANK YOU FOR ANY HELP U CAN GIVE

 

[DieselMonk]

You ever checked compression with a compression tester on these 2 cylinders? Maybe also hook up shop air to the spark plug hole to the affected cylinders and have a listen to the air intake and exhaust. Look at the inside of the cylinders using a bore scope (cheaper than taking the heads off). If you are in front of the vehicle, cyl 1 and 3 are on the left bank with the first one looking at you being #1. They are numbered from 1 to 4 on the left bank and #5 (closest one to you on the right bank) to #8.
Do a smoke test.

 

[gschacke]

Haven't done compression test wat I did forget to say is with those two missing I could watch the live data of the miss fire and if I took something heavy and started tapping on the fuel rail the miss fire rate would change one cylinder would slow down on how it would miss fire it's why I changed injectors but if I start tapping the fuel rail the miss fire rate changes or will jump to the cylinder number 2 and they all three miss fire then it goes back to 1 and 3 with 3 miss firing at slower rate if any of that makes sense cuz it don't to me and u can hear the change at idle when it does

 

[k4vbb]

High EGR pressure is an indicator that the truck has a clogged exhaust. Check your long-term fuel trims to see if its running lean--I bet it is. You can also remove the upstream O2 sensors and see if it runs a bit better. If it does, these are all symptoms of a clogged catalytic converter.