Problem 1. po353 coil C circut failure.

OK so I get probably had a bad COP but which one is "C" at $40 a pop I really don't want to change them all.

I understand Firing orders is 1-2-3- etc but what is A B C mean?
If C = 3 how does it go for the 97 5.4 L(code not litre) does 1 start pass or dr side, and is 1a-2b-3c-4d, 5e, etc or ??

problem 2. Also keep getting O2 heater circut failures (even befroe coil failure)

Been reading some blogs that seldom does o2 sensors failure actually replacing fix usally another cause that o2 sensor trips a code and replacing a o2sensor does not fix it, But being just a heater circut and not rich or lean issue I'm thinking could just be the sensor itself. Is there a bench test for them maybe an OHM meter??

 

Replace all the cops. You can buy a complete set of 8 on Ebay for about 80 bucks. Search for DG508 and buy them from Global Automotive or Uneek Supply. Keep the old cops around for spares.

Generally, O2 heater circuit failures are the sensor itself, but it COULD be a pinched, frayed, or partially melted wire - inspect those carefully. If you have over 100k, it would not hurt to replace both front sensors on general principle. Recommend you use Bosch or Motorcraft, rockauto.com has good pricing.

 

The "C" coil is #3. 3rd from front, passenger side. Check the connector mating first.

You might try identifying your vehicle accurately including the model year in your post. There are differences...

Check the fuse for the O2 heaters if you're getting fault codes for all 4 sensors, otherwise, post the exact fault code(s).

 

Thanks got it fixed, Didn't sem like a tight fit pulled it off w/o pinching button on bottom, but changed it with a used spare my buddy gave me anyways. He Had 7 used ones he gave me 3 of them.

Thought "97 5.4 L(code not litre)" would surfice guees I could add f250 light duty 4x4, didn't think body mattered when talking about the motor. edited profile now too.


not all 4 just front 2. Will post exact codes when they pop on again, cleared them after fixing coil