Rough idle..

S

sacsfin3st

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Last night I started up the LS and it started idling really rough. It drives relatively fine, but at idlel is really noticeable.

On Sunday I added a little bit of a sound system, two alpine 12's and a Sony xplode 2000wt amp. (Ofc the xplode is highly overrated for its wattage) This accompanies my hifonics 600x4 Zeus.

Everything ran fine until last night. I uncooked the subs so it is just the hifonics amp push on the mids and highs.

Would the addition of the 2nd amp cause these symptoms?

Or is it simply time for a tune up? I bought the car roughly a yr ago and have only done oil changes so far.

I'm going to have the computer scanned today to see if its telling anything. The CEL light does not come on yet. It simply idled really rough now.

Please help

Ty
 
It would help to post what flavor of LS you have. I believe it is a 2000 V8?
Maybe you have run your battery low and your alternator is struggling? Check voltages.
Maybe it's coincidental and you need coils and plugs, or maybe it is some other unrelated problem.
 
Coils & plugs were replaced when? With what brands? Is this a constant condition or a one time event? I had a rough idle once, a year or so ago, that cleared itself after a restart. It has yet to return.......
 
Unsure when cops were changed.

Yes 00 v8.

I disconnected 2nd amp to attempt to help alt, symptoms remain. Ill check volts when I get hmm today.
In the year I've had it. Its never done this. And so far hasn't gone away. So constant now but never before this.
 
As a side note. When I got car. It was getting roughly 16-18mpg. This past month, its been dripping dramatically. Now it is getting 14.5.

Cops maybe?
I have a fuel filter to put in as well but would cops cause this?
Also. Am I wrong in assuming bad coils/plugs would throw the CEL light??
 
sacsfin3st said:
Unsure when cops were changed.
Click to expand...

Member since March 2013, you should know better! Replace all COPS and plugs with Motorcraft or Visteon (good luck finding the Visteon's) - no other brand. Gap plugs correctly. If oil is present in wells, replace VGCs while at it.
 
Do the 00 models have check charging system indicators??
I see nothing on the dash coming on that would let me know charging system is failing.
 
sacsfin3st said:
Do the 00 models have check charging system indicators??
I see nothing on the dash coming on that would let me know charging system is failing.
Click to expand...

Roll through the information displayed in the message center. One should be "charging system....."
 
Ok says charging system ok. Could that rule out alt? Still plan on checking voltage. Just thiught I'd throw that bit of info out.
 
sacsfin3st said:
Ok says charging system ok. Could that rule out alt? Still plan on checking voltage. Just thiught I'd throw that bit of info out.
Click to expand...

It's just telling you that the little red light that looks like a battery (you do have that) is not on. It's not 100% correct. Sometimes the alternator fails without triggering the light.

(Turn your key to run, but don't start the engine. You should at least see the check-engine light, the battery (alternator really) light, and the oil light.)
 
joegr said:
It's just telling you that the little red light that looks like a battery (you do have that) is not on. It's not 100% correct. Sometimes the alternator fails without triggering the light.

(Turn your key to run, but don't start the engine. You should at least see the check-engine light, the battery (alternator really) light, and the oil light.)
Click to expand...

Yup.... Happened to my wife's LS. Alternator was dead/marginal without triggering the warning in the message center.
 
So on the way home the CEL came on. Ill have a scanner over here tonight or in the mornin.

Turning the key to run but not starting does indeed show the CEL, battery and oil light all came on then went away per normal. But now my CEL is on. Time to kiss another G goodbye. Just put new tires on her 2-3 wks ago. I'm really leaning towards a major tune-up. New cops, fuel filter and oil change. Any thing I am missing??
 
Ha. Ofc. That is a definite. Ty for all the info. Ill keep you guys updated with info as I get it
 
I would also check the wells for oil, if there is a decent amount - might as well do the VGCs at the same time.
 
I Will make sure to check that off the list.

Would oil in the wells burn off thru exhaust? I don't have any smoke coming from exhaust ever. No condensation either...
 
sacsfin3st said:
I Will make sure to check that off the list.

Would oil in the wells burn off thru exhaust? I don't have any smoke coming from exhaust ever. No condensation either...
Click to expand...

No it will just sit there soaking the coil. Some oil is ok, but if the coil is bathing in oil you should change the VGC's. Fel Pro and Motorcraft are both good options.
 
Nice. Now aftermarket sound systems kill the COPs. And another one down and another one down, another COP bites the dust, hey, we gonna get yours too, another COP bites the dust!

And for any NSA members sniffing around, COP does not mean the police.
 
i like how you smart guys diagnosed his cops as 'killed' without even asking what the CEL is for.
what does the code say bud? rough idle can be caused by lots of other things too. are you running the correct octane of fuel everytime? is the fuel filter good? when is the last time you ran injector cleaner?
 
LS4me said:
Marginal/failing coils rarely throw a code....
Click to expand...

Actually, in my experience with a #4 misfire, under load, (WOT) it would only rapidly blink the CEL on the dash and then go away during same drive cycle. Had to hook the scanner up to it, WOT, get the flashing CEL, pull over, read the code immediately to obtain it while it was there.

Without clearing it, would proceed to drive on and would clear it self before I got home. Once it sees a good drive cycle, where the misfires are within tolerance it forgets about it.

Couldn't understand why I had no stored CEL codes even though I saw it blink on the dash during WOT.

Replaced all COPs and Coils and problem gone.

but there's more to the story, I ended up ofcourse putting in a new fresh MAF since one of the torque bolts was stripped in the housing,
alone with a fresh fuel filter. Was around the same time when my aftermarket intake was going on, so it all cleared up in one deal.


Anyhow, point was, a marginal coil will throw a flashing CEL but clears itself quickly during same said drive cycle as long as it remains within tolerance.
(based on my experience with a misfiring #4)
 
What is VGC? Valve Gasket Cover?

To sacs, you did install one of those massive capacitor/fuse kits with heavy gauge wiring if you are running all that power, right? Otherwise, it will suck voltage needed to keep the vehicle running. I assume you know this already, but I mention it for any noobs like me lurking.
 
BigRigLS said:
...Anyhow, point was, a marginal coil will throw a flashing CEL but clears itself quickly during same said drive cycle as long as it remains within tolerance.
(based on my experience with a misfiring #4)
Click to expand...

Sorry, but I have to correct that statement from my experience.
"Anyhow, point was, a marginal coil may throw a flashing CEL but..."

I have seen marginal COPs do neither (no flashing light and no DTC stored).
 
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