I have an ongoing problem for over a month, 96 E250-4.9 L-automatic-70.000 Miles-The problems started when the Ignition coil grounded..I could actually see sparks to the block.I replace the coil-plugs-wires-dist. cap-rotor, Van ran fine for 2 days-then Flashed codes PO171/174

Checked for vacuum leaks-replaced intake rubber couplings-ignition coil-plugs-wires-dist cap-rotor-fuel filter-coolant temperature sensor.
///???

 

I'm a little puzzled,
first, what kind of problem is your vehicle displaying?
second , the codes are for an engine with 2 banks , the codes indicate a lean condition on each bank
Did you get a chance to double check your work ?
Do you know if there were any codes in the computer before doing the work?
If so, what codes?

 

The problem started after I replaced the coil pack plugs and wires-distributor cap and rotor...It would not start -coil was grounded-arcing to the block - you helped me with that...The engine ran fine for a few days-it starts and idles fine...but when on the highway like 50 MPH or so...if you back off the gas pedal-you can feel a miss-then I get the PO171 and PO174 codes and the engine lacks power...I have double check everything...???

When I reset the codes...I can drive a few miles-and it starts again when I let off the gas at highway speeds or even below in some cases.

 

Have you checked to see if the EGR valve is hanging up and staying open ?
You might try removing and plugging the vacuum line to the EGR valve and see if it makes any difference.

 

Hanky- Thanks-I will give that a try tomorrow...I sure appreciate that information/
I couldn't find the air intake rubber connectors-obsolete-not available...I used Fernco plumbing rubber couplings...worked out well.

John

 

I decided to go ahead and try blocking the EGR vacuum line..I drove it 1.4 mile-and the PO171 and PO174 flashed..
I thought we had it,,,but we didn't...? Such a puzzle.

John

 

Did you have the codes before installing the Fernco ?
The codes indicate a lean condition which could be caused by unmeasured air getting into the engine between the MAF sensor and the throttle body. The ECM could be at it's limit to add addl fuel to compensate for too much air getting into the engine.
How is the idle quality?

 

Yes- I had the codes before I replaced the couplings..I did notice that the idle did increase after installed...not a great increase..just slightly more than before.


But it starts well and idles good...

 

Did you check the PCV valve for being stuck open or broken internally?

 

Yes- I installed a new PCV and hose with clamps.I am going to replace the Mass Air and PCM...everything else has been replaced...why not,,,Hah !
It is a real mystery that began after I replaced the coil-Wires-Plugs-dist. Cap/Rotor.Total mystery.

Thanks ,

John