Irregular idle, spark jumping

[Joshua Smith]

Hi all. New to the forum. I have an 05’ 5.4L that I could use some advice on. To start, I have little to no mechanical abilities so dumb down answer if you can. I bought the truck with 163k on it Bought it with a CEL showing 02 sensor. Got it home and noticed after the first 600-1k miles the infamous knocking. Bought lockout kit, full replacement kit (I.e. lash adjusters/guides/chains etc), programmer, motocraft plugs, and a pair of high performance COP’s. Got everything on and it ran like a top for about 3 wks. Then all of the sudden it started shaking/surging at at idle. Not horrible, no shutdowns. Just annoying. When you start it, cold or hot, in park or any hear at idle it does it. No codes being thrown. Ive finally narrowed it down to the spark jumping whenever this happens. It will shimmy at idle. When it does, my SCT shows the spark jump from 8-15 up to 25-35. It’s very brief and gone. What could this be? Bad COP? Bad plug? Where should I start? Thanks for reading and any help that comes from this.

 

[TobyU]

I'm not sure what you mean by spark jumping. Are you talking about the misfire counts on the mode 6 and test results on a scanner? Or are you talking about ignition timing advance?

 

[Plati]

Spark jumping got me too. Reminded of the SeaRay we had in the 80's.
Open the engine cover at night and there was quite the light show from the plug wires.

 

[stamp11127]

Spark timing is moving from 8 degrees to 25-35 degrees btdc. PCM is adjusting the timing trying to keep the engine running would be my first guess.

OP- how did you hold the cams in position while changing the timing set?

 

[1955moose]

Shaking, surging at idle usually is an intake vacuum leak. Strange though you were fine for almost 2 weeks. A spark relalated problem usually happens under load, although it's possible. I'm a little confused, in your opening statement you said you I have little to no mechanical abilities, but yet you did a job on your vehicle that requires not only mechanical abilities, but journeyman level expertise to do correctly. Don't sell yourself short. How does it run? Particularly under acceleration? Why did you not replace the cam phasers, and opted for the lock out kits? I'd smoke the engine through brake booster hose, you've got a hose or gasket that's leaking vacuum.

Sent from my N9131 using Tapatalk

 

[Joshua Smith]

I'm not sure what you mean by spark jumping. Are you talking about the misfire counts on the mode 6 and test results on a scanner? Or are you talking about ignition timing advance?

Not really sure. Whatever the spark degree notates on my SCT. Sorry if I sound dumb. Just not mechanically inclined. What I’ve noticed is that whenever the “surge” happens at idle, this reading spikes to 25+

 

[Joshua Smith]

Spark jumping got me too. Reminded of the SeaRay we had in the 80's.
Open the engine cover at night and there was quite the light show from the plug wires.

Are you thinking maybe one of the COP’s is loose? Bad?

 

[Joshua Smith]

Spark timing is moving from 8 degrees to 25-35 degrees btdc. PCM is adjusting the timing trying to keep the engine running would be my first guess.

OP- how did you hold the cams in position while changing the timing set?

Had a mechanicaly Knowledgable buddy do the work and I “helped”. First time was using a wedge tool and he installed lockouts. Once this occurred, he did not know. So, I he suggested phasers were bad. I didn’t agree but opted to change them anyways. Took it to a shop and installed OEM PHASERS. no change in this issue. Now I’m running OEM phasers which I did not want to do and still have this issue.

 

[Joshua Smith]

Shaking, surging at idle usually is an intake vacuum leak. Strange though you were fine for almost 2 weeks. A spark relalated problem usually happens under load, although it's possible. I'm a little confused, in your opening statement you said you I have little to no mechanical abilities, but yet you did a job on your vehicle that requires not only mechanical abilities, but journeyman level expertise to do correctly. Don't sell yourself short. How does it run? Particularly under acceleration? Why did you not replace the cam phasers, and opted for the lock out kits? I'd smoke the engine through brake booster hose, you've got a hose or gasket that's leaking vacuum.

Sent from my N9131 using Tapatalk

Thank you for the vote of confidence. I should have clarified. I had someone “handling” the job. I helped. Truck runs fine. Never stalled. Never feels like it’s going to. Just this dang surge at idle. Read up that lock outs deleted the problem. So I opted for them. Once the surge arrived, I allowed myself to get talked in to replacing phasers. No change.

 

[Joshua Smith]

Thank you to everyone helping troubleshoot this. I apologize for the late responses. I’ve been out of town on business. I am getting a few codes that keep returning. Not sure why. However, I will state that I had these prior to any of this work being done. Again, thank you to everyone for taking the time to troubleshoot. It is appreciated.