03 misfire

[Kipp]

Obd on my 03 Eddie Bauer reads misfire on start up first 1000 revolutions, and misfire on cylinder number three. I’ve changed all the plugs to Motorcraft parts changed all the coils to Motorcraft and now the OBD says misfire on cylinder number one. Checked it again the other day and now it says misfire on cylinder number four. I have been told that this year 5.4 triton motor they change the coolant hose to a metal pipe that runs under the intake manifold I sure hope that’s not what’s wrong with it?

 

[Hamfisted]

Cylinder number one P0316 code can be a coolant leak in the intake right there at the crossover pipe/manifold joint, or it can be a leaking head gasket on that cylinder. Are you getting any exhaust gases in your coolant reservoir or traces of soot ? Do you have a coolant system pressurization kit ? Any coolant leak visible there at the crossover pipe near cylinder #1 ? (Cylinder #1 is front cylinder on passenger side...).
Are you having any coolant blow out of the reservoir yet ? So it can be just an intake manifold/crossover gasket leak, or worst case, a bad head gasket.


Coolant System Pressurization Test Kit on Amazon







Ford Triton #1 Cylinder Misfire & P0316 Code








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[Kipp]

Would that make it jump around misfiring different cylinders intermittently?

 

[Hamfisted]

No. What codes are you actually getting ?

 

[Kipp]

Po316,po301,po304,po303

 

[Hamfisted]

Ok, that's sounding more like bad head gasket(s) . You can pressurize the coolant system while watching for misfires in mode 6 (ForScan app ....). See if pressurizing the coolant system introduces misfires in those cylinders.

 

[Andrew McDowell]

The tell tell sign to me is engine misfire on cylinder # 3 (Passengers side, next to the last cylinder). I had the same issue... it was the classic 5.4L timing chain tensioner gasket blow out, which caused low oil pressure on the passengers side cylinder head... and therefore damage to the valve train. Removing the valve cover on the passengers side will confirm the rocker is either worn or completely misplaced, mine was worn, not flat and not misplaced. My camshaft lobe however, was definitely worn down. My Navigator needed the repair at 140k

I wound up replacing the passengers side cam all my lifters and rockers, timing assembly, water pump, oil pump, phasers and injectors.
I had to make up heater hoses from ends I acquired from the local parts store, Y pipe and heater hose.

Its a big job for sure, involving several weekends if you do it in-frame.

I concluded after doing the timing job the first time, that if I ever had to do it again, I would pull the engine to do the job, because you would have much better access. The job in-frame involves some contortion, reaching down from the top and up from the bottom and attempting to squeeze your hands into the limited rear cylinders, especially when installing the rockers.