I have a 93 Ford F150 w/ 5.0 fuel injected V8 engine

My mechanic and i have been trying to figure out this issue im having with the engine not running right, it seems to be skipping and when driving sometimes around 30-40mph it will start to buck real bad usually going up hill at a lower RPM and i will have to let off the gas and hit it harder to make it stop.

We have replaced a whole bunch of parts and still hasn't fixed the issue. We did a full tune up with spark plugs, wires, cap, oil, filter, air filter also replaced the lower intake, coil, EGR valve and sensor. We checked the compression and spark and it all seems to be working properly, the compression was a little bit low on one side but still within a decent operating range. Also just recently fixed the emissions pipe that was connected to the exhaust.

I had the diagnostic run and it spit out a few codes.
-Knock sensor not detected
-Thermactor AIR system inoperative during self test
-EGR sensor below min voltage
-And this one



I can't quite make it out but somebody might recognize it
(I took pictures of them all so i would remember them, this one just came out really crappy sorry)

So my mechanic says he can only think of 2 more possible things to replace to try and fix it
which would be the distributor or the fuel injectors.

What do you guys think?
Any help or suggestions would be greatly appreciated.

 

you sure its misfiring and not just because its bogging down at a real low rpm in overdrive? mine kinda shakes a little bit between 35-40mph only in overdrive but its because its at a real low rpm

 

I am sure. If i have it in overdrive it will do it also but usually around 40-45
It defiantly shakes but not just a little bit
Not to mention my mechanic can tell its not running right as soon as its started.

 

Double check your spark plug wire routing. It's easy to cross 2 cylinders, and if the wires are not routed correctly, you can get inductive crossfiring too.

 

Spark plug wire routing is correct.

 

~bump~

Found some paper work in the glove compartment that says there was a rebuilt engine put it. Any chance they forgot to hook something up properly when they put it in?

 

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