I could sure use some help - My 96 E250 suddenly was hard to start-I changed the plugs ( Autolite ) new plug wires - Distributor cap/rotor-new ignition coil.
It now starts fine- however-now when driving at highway speeds-if you slow down-back off the pedal to near idle-it stumbles slightly-if you continue not to accelerate-it starts missing...The miss is slight-but if you continue to back off on the engine speed--it will eventually shoot a PO300 code.
The Van has 70,000 miles,I would appreciate any suggestion.I also looked everywhere for a vacuum leak - but no success locating.

Thanks

 

From my experiences, I had less problems with Motorcraft plugs in Fords.
Had to learn the hard way, a lot of aftermarket stuff out there is cheaper, but the quality just is not there and some were defective right out of the box. The code could involve any of the parts you replaced. Random misfires can have many causes and somewhere along the line complete info is not getting to the PCM. It could be from a loss of crank signal at times to lean misfire .The 4.9 was pretty reliable. What other engine maintenance has been done, like fuel filter ,air filter etc.? EGR systems can also get into the pix.

 

My 96 E250 -4.9" needs fuel lines-which are not available-obsolete-no after market--are there any options ?

 

Which lines?

 

The supply and return fuel lines from the fuel filter to the engine.

 

You might try ,Vintage Parts Inc
Beaver Dam, Wisc.

 

Thanks for the help=as always

 

Thank you !!!