1996 F150 4.9l running rough when hot

ford

#1

I have a 1996 Ford truck with a 4.9L engine that after warming up the engine runs really rough.
When I drive like this I can get it to run better after driving a while. But,
if it sits for a while it will start right up and run good until I shut it
off again. I get two codes 0171 and 0174 which engine runs too lean in bank 1
and 2.
I change the distributor, ignition coil and ECM for ignition .
Replaced EGR and EGR solenoid, idle control module, MAF sensor, thermostat, temp
sensor for computer and engine, hotter spark plugs, replaced injectors, and
all 3 oxygen sensors. Please help


#2

What is the milage? Did you get a compression test?


#3

Why?..were the ones you took out black?


#4

Yes I did a compression test and the range was 156 to 160 per cylinder. The mileage is 277,576 miles.


#5

There was no real reason, I was trying anything.
The spark plugs I took out were in good shape and white.


#6

Have you tested the fuel pressure?

Especially the residual fuel pressure?

Tester


#7

no, I have not tested the fuel pressure or residual fuel pressure. where do I do that at? Thanks