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02' Deville (H.G. club-sold) 02 DTS black on black
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62 Posts
Discussion Starter · #1 ·
sometimes my deville idles rough right when you start it, and lately it seems to be getting more frequent. a few times now its idled rough at start up when the car had only been parked for 30 mins or so. I dont have a check engine light on and no current codes are present either. i have only had this car a couple months and either didnt notice the problem right away or it just started a month ago. it only has 50k miles, but could it be the plugs starting to foul? :confused:
 

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1996 Deville (sold), 2000 Mustang GT
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1,300 Posts
Same here, rough idle was the begining of the end. It could be simple though, theres a couple things thatll contribute to that besides failing headgaskets. Some of the cheaper things to replace; air filter, fuel filter, fuel pressure regulator, plugs and wires. Another highly likely issue is your crankshaft position sensors, those aren't cheap.
 

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Super Moderator
2010 DTS
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88,005 Posts
'02 is COP (Coil On Plug) ignition so there are no wires. CKP sensors will usually cause the engine to die rather than idle rough, but will eventually need to be replaced on an '02 if they haven't been already. I don't think they are that expensive though. Air filter won't cause a rough idle either. A dirty TB probably won't either, but it can't hurt to clean it and is probably due by now anyway. FPR would certainly be worth checking. Fuel filter would not have any effect on idle either.
 

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02' Deville (H.G. club-sold) 02 DTS black on black
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62 Posts
Discussion Starter · #6 ·
coolant level is always full. it only idles rough for about 60 seconds when its a dead cold start, and about 20 or 30 secs when its been restarted during the day. some days it doesnt do it at all. How do you clean the throttle body? carb cleaner spray?
 

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1996 Deville (sold), 2000 Mustang GT
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1,300 Posts
How rough does it idle? It sounds alot like my Deville 1000 miles bb4 the head gasket went, but it really had a pretty violent idle for about 45 seconds. It may be time for a tune up. Try cleaning the throttle body first, theres a write up in the tech tips section, DO NOT go overboard with the throttle body cleaner, it has a tendency to create issues if too much gets in the intake manifold.
 

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02' Deville (H.G. club-sold) 02 DTS black on black
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62 Posts
Discussion Starter · #8 ·
its pretty minor but i can feel the engine has a slight miss, if you rev it its still there. But after about a min it runs perfect. ill try cleaning the throttle body see if it helps.
 

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02' Deville (H.G. club-sold) 02 DTS black on black
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62 Posts
Discussion Starter · #12 ·
you guys are freaking me out here:eek: so the rough idle is cause from coolant leaking into the cylinder when it sets? if thats true and the head gasket is leaking i should be able to pull the plugs and see if one of them is wet or oily right?
 

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99 Seville STS, 08 STS4 N* 1SG F55
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3,516 Posts
Previously you posted that its not losing coolant. Ergo, if its not using coolant, it shouldn't be the head gaskets :confused: Ipso facto, I'd look somewhere else. OK, I'm out of Latin... :bighead:
 

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02' Deville (H.G. club-sold) 02 DTS black on black
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62 Posts
Discussion Starter · #14 ·
it seems on this board any problem you ask about from tail lights to cd players somebody brings up a blown head gasket.
 

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2010 DTS
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88,005 Posts
The symptoms you describe COULD be related to a head gasket. You need to do what we told you to confirm or rule it out.
 

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2000 Crimson Pearl DTS
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56 Posts
These were symptoms of MY headgasket problem. When they pulled the plug it was wet.

I would listen to Ranger and assume that it is an easy fix.
 
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