04 LS V8 Rough Idle

[Destineal]

I really hate to be this guy, but I'm at work and don't have much time to search. On the way to work I stopped @ Academy to look at some sneakers. When I got back to my car it was idling rough. I thought it might cut off so I cut it off and tried to connect to it with the torque app. It was taking too long so I turned the car back on and the idle was kind of rough, but I finished my drive to work. Under load the engine seemed to perform as expected but of a 32V V8. Is this the dreaded coil issue?

 

[AmsterDutch]

I really hate to be this guy, but I'm at work and don't have much time to search. On the way to work I stopped @ Academy to look at some sneakers. When I got back to my car it was idling rough. I thought it might cut off so I cut it off and tried to connect to it with the torque app. It was taking too long so I turned the car back on and the idle was kind of rough, but I finished my drive to work. Under load the engine seemed to perform as expected but of a 32V V8. Is this the dreaded coil issue?

Could be several issues causing a rough idle ...a misfire is always a possibility...you need to check out any pending code(s) on the PCM ....if it’s not detecting a code, then it’s possiblely a marginal COP ...speaking from experience...I had intermittent COP’s and plugs misfire long before the MIL came on...I could tell it was misfiring but kept driving my LS until finally the MIL turned on so I could see it was cylinder 3 on the scanner...I mean you could do a full COP and plug replacement but without knowing for certain ...why would you drop $500+ dollars? I would want to know for sure ....

 

[Destineal]

No codes, but I have replaced one plug and cop since I got the car. I know that means they all should be changed so it's on the agenda.

 

[joegr]

While it could be almost anything... In general, marginal coils show up more under power than idle. Air (vacuum) leaks show up more at idle than under power.

 

[Destineal]

Good point

 

[04_Sport_LS]

Try cleaning your MAF sensor... using cleaner specifically for MAFs.

Milage on vehicle???

 

[lincoln_zero]

While it could be almost anything... In general, marginal coils show up more under power than idle. Air (vacuum) leaks show up more at idle than under power.

I will second that.
IIRC, back in 2009, my 02 was a bit funny at idle and made loud whistle sounds until I replaced the stock intake with a custom built one by SPSully. Ran like a dream, never had any idle issues. Also tuned it (highly recommend you do this, contact Torrie Tunes). I did have the COPs go bad, but that's LS stuff on a yearly

EDIT: Your vacuum leak could be anywhere obviously i'm not suggesting replacing your intake will solve this. But for me, the crap stock intake was a problem.

IMHO, I'm a firm believer (as these guys know) that the less Ford parts you have in your car and the more aftermarket, the better the LS becomes.

 

[Destineal]

I will second that.
IIRC, back in 2009, my 02 was a bit funny at idle and made loud whistle sounds until I replaced the stock intake with a custom built one by SPSully. Ran like a dream, never had any idle issues. Also tuned it (highly recommend you do this, contact Torrie Tunes). I did have the COPs go bad, but that's LS stuff on a yearly

Do I need a SCT for that?

 

[lincoln_zero]

Do I need a SCT for that?

Yessir. You can get one off eBay for a lot less than I can, cause im in Canada and we get duty fee's. LOL.

I'd recommend buying the street tune and track tune from Torrie. Econo tune is ok, the street tune gets you better economy anyways (than stock).