Hey folks,

Just completed a phaser and chain swap. The truck ran BEAUTIFULLY for over a week. Strong. Smooth.

Then about a week and a half after I replaced the phasers it started to misfire while driving. Made it in to AZ and had them check the codes... 12 in all...

p0174- system too lean bank 2
p0308- cyl 8 misfire
p0174(again)
p0300- random misfire
p0351 thru p0358- ign coil A thru H (cylinders 1-8 primary/secondary circuit)


Last night I pulled the coil wires on 1 cyl at a time while it was running and 5 of 8 made no difference in the idle... 5!!! I do not see any loose lines or wires anywhere on the engine.

Truck has 142000 miles. I have read a ton of stuff on here thru multiple searches. It just seems odd to me that all 8 COPs would crap themselves after the phaser change. Is this normal???

I am ready to shoot this truck. Help!

Thanks- Steve

 

Wow good luck...im just tagging along to see the outcome.

 

I do not believe that a 5.4 will idle on three cylinders. In more specific terms, I do not believe that you could disconnect the 5 coils that made no difference, all at the same time, and still have the truck idle.

I do believe that disconnecting them one at a time made no apparent difference.

Conclusion is that 3 cylinders are strong, 5 are weak. Since you didn't bother to enumerate the strong and weak cylinders, I have one wild guess:

One bank, 4 cylinders, is messed up, either the cam is off or the fuel rail or some other component is malfunctioning. One cylinder on the other bank has a bad cop or injector.

If you do shoot the truck, please specify which cylinder and caliber.

 

cyl 3 and 4 and 5, 6, and 8. Indeed, I unhooked 1 at a time in sequence. The 3 cyl not mentioned made a HUGE, noticeable diff when unplugged, so that tells me they were working.

I did not try to run or start with 5 coils unplugged...

Owner feels last service shop may not have changed plugs or used platinum tipped models. My contention is why is it crapping itself now... same argument for COPs applies to plugs, IMO.

 

Then it appears that cylinders 1 and 2 are working normally on bank one, and cylinder 7 on bank two. If that is the absolute truth, then I would rule out the cam timing and phasers.

A compression check would be my next step. I would also repeat the coil disconnects and double check that you get the same results for the same cylinders. I would also place a new plug on the disconnected cop to make sure it is a good, hot, blue spark.

 

Just had a thought... I removed the timing chain cover when I did the chains, and as a result removed the crank trigger... it went back on as it came off, with the "fingers" facing forward (towards harmonic).

Maybe 2 thoughts-

1- I wiped off the crank sensor with a rag as it had some metal on it from where previous chain debris on it...bad ??

2- reused harmonic bolt... learned after that OF COURSE its F'N TTY. I am about to run out and look... I wonder if that sucker is about to give?

UPDATE: Harmonic is not wobbling whatsoever.

 

Did you read TSB 04-24-24.

Were any of the parts you used for the 2004 5.4L 3V?

Just a thought.

 

No I did not and to my knowledge, no sir. All parts we requested were for a 2005. Will read the TSB now.

 

I read the TSB- did not change cams and lifters, only phasers and chains.

 

Subscribing. Wish I could help, but unfortunately my misfire was a simple fix, 1 bad cop, ended up replacing all of them just to be safe that it wouldn't repeat itself. Good luck and keep us updated.

 

Wiring IMO Check the harness. Check PDB fuses. Your intermittently losing power to all 8. Something was bumped or damaged (wiring). Make sure the harness has not contacted the AC accumulator or very close to. If so, tie back. The mag field can create ignition havoc. Specially if any of the wires loose their foil insulation.

It has to be intermittent. Otherwise the engine wouldn't run, via 351-358.

 

OK, I will check it again. Owner wants to pull plugs and I just dont a)think they instantly all crapped themselves or b)want to risk a breakage.

It starts fine, high idles great, then once it idles down misfires like a biznitch.

 

jbrew- do u mean compressor as opposed to accumulator?

 

Nope.

 

Yea , the AC accumulator. Not the compressor.