Part po351 - 1997 Ford Expedition

PO351 = Ignition Coil 1 Control Circuit

Codes for ignition coils are not always accurate

You can get many codes for many cylinders & have one or more
bad coils

I would do a cylinder leak down test, to eliminate a mechanical
valve sealing issue

Then if all valves seal-- smoke the intake for vacuum leaks

PO301,PO351 or Coil A -- are all the same-- cylinder #1

Misfire could be bad coil,plug,wire.

There are a million web-sites out there that offer free listings of the trouble codes. Go to Google, simply type in trouble codes for your year VW, model and engine size, you will get multiple listings.

Could be it,here's a link to it.Here's the sensor.

not sure the exact ford you have but that is an ignition coil circuit malfunction

It's probably the 4th which is all the way in the back on the left side when you are standing in front of the vehicle facing the engine. There is a water line that runs above that cylinder and drips condensation into it allowing for problems. It's best to replace the plugs AND the (coil pack--which run $60 each).

po351 code is ignition coil peak primary circuit current not achieved with maximum dwell time.

http://forums.cnet.com/7723-7811_102-270706/97-jeep-grand-cherokee-stalling-not-fixed-yet/

what module is it in?