2013 Roush Raptor - Misfire under load

[WNB]

Hi Everyone

Need advice

I am an expat living far away for decent support and have used this form etc to keep my beloved 2013 Raptor with 190,000km on the clock a true Raptor.

Symptoms

Cruising at any speed, if I excelerate lightly, I get the occasional misfire (without triggering a a engine light).
If I accelerate hard, the misfire is very prominent and start getting a flashing engine light.
No Idle issues
If the vehicle is in Park/Neutral and I Rev it up - no misfires
Seems to only happen under "Boost"

Done to date
Replaced Coil packs with OEM
Replaced 16 spark plugs with sam Iridium's as before (and Gapped as recommended)
New MSD Spark plug Wires
Replaced the Engine Wiring harness loom with a new OEM
Replaced fuel injectors from ford performance - Check model with Roush
Tested Purge Valve - Good

Any advice ...... PLEASE

 

[pat247]

Have you run a fuel system cleaner through the truck? I recomend BG 44k every 10-15k miles, it keeps the fuel injectors in tip top shape.

 

[WNB]

Have you run a fuel system cleaner through the truck? I recomend BG 44k every 10-15k miles, it keeps the fuel injectors in tip top shape.

Yes - and forgot to say...replaced all fuel injectors with new

 

[pat247]

Have you changed where you buy fuel for your Raptor? If not try a different brand of fuel for a couple of tanks.

 

[WNB]

Have you changed where you buy fuel for your Raptor? If not try a different brand of fuel for a couple of tanks.

Thanks for your msg. Yes - Changed Fuel supplier

 

[FordTechOne]

You may have a fuel system related issue. Misfire under load is typically ignition related, but with all components being replaced with OEM the next most likely possibility is fuel pressure dropping under load.

I’d start by checking Fuse 27 in the Battery Junction Box under the hood. The fuse terminals can overheat due to under spec current capacity. There is a TSB to relocate the fuse to a new location in the junction box.

If the fuse has already been relocated, you can proceed by checking fuel pressure with a manual gauge. It’s often helpful to tape the gauge to the windshield so you can monitor it under load.

 

[EricM]

What plug gap are you running?

 

[MTF]

What plug gap are you running?

Yeah, good catch, OP said "gapped to specs", don't know what that means but Supercharged 6.2L needs to be .28
Factory gap is like .40, supercharger would just blow out the spark.

Also, a weak battery even if it's a new one will produce misfires.
It needs to be 13-13.2 or higher (but on lower than 12.7) when truck off and 14+ when running