Bought this truck a few weeks ago and it runs great. A hell of an upgrade from my 02 screw 5.4. It rained last week and I threw a PO430 code so I cleared to see if it would pop back up. Fast forward to yesterday, rained again this time threw both P0420 and P0430 codes. No other codes. There's some minor rough idle when engine is cold that I don't know if it's been like that from the start and I'm just now noticing or it's new.

Could use some advice in diagnosing and fixing this.

I have a obdii Bluetooth scanner and torquePro that I'm in the process of learning to help with future troubleshooting that's needed so I have that if you have some guidance to offer to test the truck.

Also, is there any way to use forscan to remove any "tunes" previous owner may have Insalled?

Thank you for any and all help

 

Sounds like you need new cats. If the spark plugs have more than 40k on them they need to be changed.

 

How good of mileage will I get out of the coils? There's 113000mi on them

 

Can't predict that. Start with the plugs and some Techron in the gas. Might want to do a compression test when you have the plugs out. Get the cats tested for backpressure.

 

So it's not rain related. Cleared the codes, cleaned connectors and we've had some good weather and codes returned. While investigating I did find a nice hole in the front of the resonator. Would this cause the codes? Plugs replaced and techron added.

 

It's possible. Fix the exhaust and see what happens.

 

No go. My son has a 2014 and he informed me the holes are actually condensation holes drilled out at the factory. Never would have thought.

 

Have you had the exhaust tested for excessive backpressure?

If it's been driven for any length of time with a misfire, that will melt the guts in the cats, which can cause blockages and WILL throw efficiency codes.

 

Just an updated to this in case anyone else runs across. I replaced all plugs with motocraft sp-580 plugs, left them gapped as is (think they were .31) and cleaned all 3 MAP sensors and the codes have not returned after almost 2k miles. Pretty sure the plugs were original factory plugs. Guess having 112k mi on them wasn't good