Looking for some help. Here is some background.

2000 F250, 2 wheel drive, 5.4 with automatic transmission.

My truck was in a minor accident 6 years ago and without full coverage insurance or the money to repair it I just let it sit in the driveway.

The damage was to the drivers side front bumper, drivers side fender, truck bed and rear bumper (from my spinning in the road after the initial hit, and the rear of the truck hitting the concrete median).

Finally decided to get the truck running again. Bought the sheet metal, bed, newer model front end sheetmetal/lights etc.


Did oil and filter change, new battery.

Dropped fuel tank, drained all fuel, cleaned tank, wiped it down inside as far as the arms would reach.

Filled with 5 gallons of new gas.

truck would not start up and found fuel pump was bad.

Dropped fuel tank again.

Replaced fuel pump.

Truck started but had a misfire, kept it running by giving it more pedal. Failed to realized that in doing so, I was sending unburned fuel through the manifold into the exhaust. Started a fire under the truck, with the composite cover over the catalytic lighting up. Mobile mechanic stated the catalytic was damaged from the heat.

Since this truck only came with upstream O2 sensors on each side, just removed the catalytic and straight piped it to the muffler.

Checked all wiring underneath and verified no other damage.

Replaced all plugs with motorcraft plugs, replaced COPs.

Removed and cleaned all injectors.

Replaced fuel pressure regulator.

Replaced fuel filter in the drivers side frame rail.

Truck starts and runs fine often, but not always.

Pre accident MPG was 16mpg in my city driving
Current MPG is now 10.4mpg in city driving.

Occasionally, the truck will lightly hesitate both under load and under regular light acceleration. When this happens, it also pings a little.

Other times, the truck runs perfect, accelerates like a best with zero noticeable issues.

Checking the fuel pressure at the rail this is what I find.

At turning of key without starting truck: 30 psi, then it immediately drops to zero.

Starting truck,while at idle: 30 psi

Pushing it to 4000 rpm, : 30 psi

Pushing it to 5000 rpm: 30 psi

Just in case, removed all 8 injectors and replaced them with new injectors.

After removal, had my 8 injectors checked. All worked fine. Dirty only. None stuck open, none leaking. Had them cleaned and new filter baskets and o rings installed. Set them aside for future use.

I have also just in case, moved COP's around to see if the misfire follows a COP.

Took the truck to Ford on Monday. informed them of the occasional hesitation/surging, of the fuel pressure data and of the terrible drop in fuel mileage.

They had the truck for 5 days until this past Friday.

Tech tells me there is a misfire on 8 and 7.
Claims the fuel pressure being at 30 psi, and that it dropping to zero immediately if the truck is not started is not a problem.
States the drivers side O2 sensor shows some erratic data.

States that since the truck is not throwing any computer codes, they don't have much to go on.

Moved COPs around again, and the occasional misfire remains constrained to 8 and 7.

I was willing to pay dealer prices to diagnose this issue and possibly even dealer price to fix it. I got the truck after a week with zero usable information in my opinion.

Yesterday I bought a new O2 sensor at Advance Auto Parts and installed it.

I still find the same hesitation today.

I am in desperate need of experienced thoughts and suggestions on this. My truck has 151,000 miles and is otherwise in great shape.

Seems like all of my trucks are having issues. I still need to find a resolution to my oil spitting 99 V10 F350 and now I have this truck acting up. Help please.

 

This might be a stupid question but have you checked all your vacuum lines to make sure you have no leaks and they are all connected and check the little elbows and tees as well to make sure they arent leaking, a vacuum leak could cause you issues like that.

The other thing I would check is harness to the injectors, and to the COPS and make sure there is nothing loose or the connectors arent broken. Other thing I would look at is to make sure the gaps on your spark plugs are all in spec

 

all of those things have been looked at. the only vacuum line not checked thoroughly is the main one going to the passenger side pcv valve. I cannot tell where it leads to from the valve cover.

 

Are you talking about the one vacuum line that snakes all the way to the rear of the engine to a post just below the IAC ? did you check that one to make sure there are no leaks in the fitting or line. Hmmm have you checked the fuel pressure coming from the fuel pump in the tank? I would also change your PCV valve if you havent already could be it has a build up

Obviously your getting fuel, but It could be your fuel pump in the tank isn't putting thru enough pressure when it is commanded on I would check that and make sure there is nothing in the tank that is causing the pump to get clogged. I would check the pump for sure. It could be your pump is not putting thru the pressure needed.

There are guys who have added fuel additives and not realized that the little liner in the fuel additive cap stuck on the bottle when they dumped it in and down into the tank it went causing fuel pressure drops and starvation. You might also want to check the throttle body and make sure the ports on it are clean

 

I mean to mention did you have a look at your EGR valve to make sure it isnt stuck open, that will cause a vehicle to misfire