‘13 Lincoln MKS 3.5 EB P0301, P0302, P0303 misfires under heavy load

[HatoriHanzo]

Hello all, I recently picked up a 2013 Lincoln MKS 3.5 EB and just took it to the shop for a water pump replacement. Upon picking the car up it ran fine (as it did when I dropped it off) within 30 miles of driving the C.E.L. came on and I lost power. Turned the car off and restarted and I could drive under regular throttle but as soon as I hit the throttle and expect to take off the car falls on its face. The car had 150,000 miles in it and I realized the plugs were OE (oops) so I changed them out and swapped the coils front to back to see if the codes followed the coils (nope) no change. It's  going back to the shop as I feel they didn't do something right on reassembly. Any help would be great, thanks.
Mark

[TopherSho]

Does the CEL flash and then clear on its own?  And does it produce any codes ?

[HatoriHanzo]

Yes, there are codes, P0300, P0301, P0302 and P0303. It does flash and then go out. I shut the car off and restart and am able to drive it normally.

[ridered74]

Yes, there are codes, P0300, P0301, P0302 and P0303. It does flash and then go out. I shut the car off and restart and am able to drive it normally.

P0301 is a cylinder 1 misfire, P0302 is a cylinder 2 misfire, P0303 is a cylinder 3 misfire, and P0300 is a multiple cylinder misfire that google says is usually caused by a damaged or loose vacuum line.


Cylinders 1-3 are the firewall side so I would be checking all the vacuum hoses on that side of the engine. Maybe one of them didn't get put on all the way or got pinched and has a hole in it now.

[TopherSho]

Yes, there are codes, P0300, P0301, P0302 and P0303. It does flash and then go out. I shut the car off and restart and am able to drive it normally.

P0301 is a cylinder 1 misfire, P0302 is a cylinder 2 misfire, P0303 is a cylinder 3 misfire, and P0300 is a multiple cylinder misfire that google says is usually caused by a damaged or loose vacuum line.


Cylinders 1-3 are the firewall side so I would be checking all the vacuum hoses on that side of the engine. Maybe one of them didn't get put on all the way or got pinched and has a hole in it now.

Spot on .. an entire bank misfiring is *probably* a AFR related issue .. still could be fueling .. but I'd wager a leak.  Get a crappy cell phone you have in a drawer somewhere and charge it.  strap it to the rear firewall somewhere away from the exhaust pointing the mic to the engine.  record the audio.. i bet you pick up a significant hissing noise.

[HatoriHanzo]

Thank you, I will check that out. Updated info from the mech shop, fuel rail pressure drops to <100 psi under load (should be 1000psi).. replaced the HP fuel pump, still same issue.

[TopherSho]

Thank you, I will check that out. Updated info from the mech shop, fuel rail pressure drops to <100 psi under load (should be 1000psi).. replaced the HP fuel pump, still same issue.

... I find that claim suspect ... but I also have a pretty tight tin hat when it comes to mechanics/shops.  hmmm @SHOdded Do the 13's have the ability to saftey shut off INDIVIDUAL injectors ?  I am unsure...

Also,  I do not know but are the rear and front banks feed by the same hot wire?  If not the same hot wire maybe the back bank is low on voltage or has a bad ground.

[HatoriHanzo]

The shop is switching the injectors front to back to see if the problem follows. They believe that we have a bad injector under load.

[HatoriHanzo]

So, in the end the Fuel Pressure sensor ended up being the culprit.....well at least we've got the car back...

[TopherSho]

hmmm good to hear,  1st time i have heard of one going out.  How much was it ?

[HatoriHanzo]

Considering all the hours they had in diag, swapping the injectors, cleaning the fuel rail etc. We got out the door for $700. I know the tech personally and he had over 15 hours in just diag not to include the injector swap time. Extended warranty paid for the HP fuel pump. Diag time was the killer.....