Rough idle

[aaronr]

It started doing this when it got cold outside. When the truck start up it idles really rough and the whole truck rocks like it has a cam. To me a sound like it has too much fuel and sounds like missing on the exhaust. When it idles why is the spark all over the place? Here is the log file.

[Biggsy]

Welcome to the forum

Dud spark plug/lead?
The PCM is raising/lowering timing possibly to try and keep the idle rpm from falling/raising.

[aaronr]

It only started this when it got cold outside. The truck got tuned this summer.
spark plugs were change 5 months ago and plug wires 1yr ago. I think this what your asking?

[Biggsy]

I think this what your asking?

Correct.
Ive had a relatively new (less than 12 months old) spark plug lead fail on me.

[aaronr]

Correct.
Ive had a relatively new (less than 12 months old) spark plug lead fail on me.

I'm not sure I know what a spark plug lead is? Wouldn't you get a random misfire code?

[joecar]

Yes, I have had new spark plug leads fail, so check each one (you can see each of them between each coil and spark plug).

Also, other possibilities:
- air leak due to failed hose (would cause positve LTFT like your log shows);
- failed fuel pressure regulator (may go either way).

[joecar]

I'm not sure I know what a spark plug lead is? Wouldn't you get a random misfire code?

Best thing to do is have someone diagnose the problem.

[aaronr]

Yes, I have had new plug leads fail, so check each one.

Also, another possibility is: air leak.

Why only when it is cold like 50 degrees or so?

[aaronr]

Yes, I have had new spark plug leads fail, so check each one (you can each of them between each coil and spark plug).

Also, other possibilities:
- air leak due to failed hose (would cause positve LTFT like your log shows);
- failed fuel pressure regulator (may go either way).

I think pressure regulator is bad. I was told when the truck is hot and you let sit for 2hr or so it was hard to stat in the summertime.

[Biggsy]

Why only when it is cold like 50 degrees or so?

Are you talking outside temperature?
Post your tune, someone might see a problem.