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  • SN95 4.6L Mustang Tech

idles rough

  • Thread starter Thread starter 00GTpony
  • Start date Start date Jan 7, 2010

00GTpony

Member
Mar 10, 2007
162
0
16
Jan 7, 2010
#1
  • Jan 7, 2010
  • #1
My idle has been rough, the plugs are farley new... what else could it be, i no it could b coil packs but wanna check everything else out before i spend 300 on coil packs. just hit 70,000 miles
 

00GTpony

Member
Mar 10, 2007
162
0
16
Jan 7, 2010
#2
  • Jan 7, 2010
  • #2
pcv valve?.. iac?..dirty air filter ( i dont think that can cause that )
 

32ValveRom

Member
Feb 15, 2009
328
0
17
Fl
Jan 7, 2010
#3
  • Jan 7, 2010
  • #3
I had to clean my iac valve because I was idling high. When's the last time you had a tune-up?
 
K

Kilgore Trout

Fried or Broiled ?
10 Year Member
Mar 30, 2005
4,749
95
134
Jan 7, 2010
#4
  • Jan 7, 2010
  • #4
Could be any one of a million things. You will have to provide more information and/or do some inspection and maint under the hood.
 

00GTpony

Member
Mar 10, 2007
162
0
16
Jan 7, 2010
#5
  • Jan 7, 2010
  • #5
the only tune up was plugs about 20,000 miles ago, air filter i dont no when it was changed last, and the coils, pcv valve have never been changed... fuel filter about 20,000 miles ago to. i probably could use a change on that for i run it low on gas alot.

ill try cleaning my iac but my idle doesnt go high its just intermitenly rough.
 

1fun281

Member
Mar 16, 2009
438
8
19
Atlanta Georgia
Jan 7, 2010
#6
  • Jan 7, 2010
  • #6
00GTpony said:
the only tune up was plugs about 20,000 miles ago, air filter i dont no when it was changed last, and the coils, pcv valve have never been changed... fuel filter about 20,000 miles ago to. i probably could use a change on that for i run it low on gas alot.

ill try cleaning my iac but my idle doesnt go high its just intermitenly rough.
Click to expand...

Stupid question but are you leaking coolant or anything like that?
 
3

302GTS

If you need herpes, I'm your man!
Apr 20, 2009
481
2
18
Largo, FL
Jan 7, 2010
#7
  • Jan 7, 2010
  • #7
1fun281 said:
Stupid question but are you leaking coolant or anything like that?
Click to expand...
No such thing as a stupid question, brother!

Like he said, OP, are you leaking coolant, and have you checked out oil? It's obviously a long shot, but head gasket failure can always be a culprit. As for any other things other than a basic tune-up, I can't really help out as my 5.0 is a bit different than you crazy modular guys' motors.
 

1fun281

Member
Mar 16, 2009
438
8
19
Atlanta Georgia
Jan 7, 2010
#8
  • Jan 7, 2010
  • #8
302GTS said:
No such thing as a stupid question, brother!

Like he said, OP, are you leaking coolant, and have you checked out oil? It's obviously a long shot, but head gasket failure can always be a culprit. As for any other things other than a basic tune-up, I can't really help out as my 5.0 is a bit different than you crazy modular guys' motors.
Click to expand...

Thanks
Only reason i ask is because i have been having problems with my car at an idle too, and i have been leaking coolant but no puddles have been showing. We narrowed it down to im most likely loosing coolant through a intake gasket leak somewhere and im probably burning it up.
 

00GTpony

Member
Mar 10, 2007
162
0
16
Jan 8, 2010
#9
  • Jan 8, 2010
  • #9
just went outside and checked is there is just about no coolent left in the resavare. so i guess that means the head gaskets leaking?.. or mayb its leaking out of the mainifold?

oil looks fine.
 

00GTpony

Member
Mar 10, 2007
162
0
16
Jan 8, 2010
#10
  • Jan 8, 2010
  • #10
also ive had this intermitent rough idle for like 8 months, and just noticed now the the coolant is just about empty. so it took 8 months to drain.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Jan 8, 2010
#11
  • Jan 8, 2010
  • #11
Pressure test coolant system

How about starting by blowing out the spark plug holes with compressed air? Look for moisture in the holes. Look for evidence of coolant leakage. Clean.

Remember that moisture may cause the spark to ground out and this can damage the insulating boot. It is possible to buy replacement boots.

Refill the coolant to the full cold level. This will give you a known starting location.

If you need piece of mind and need to know right away, perform a coolant pressure test. Autoparts stores will rent the tool for the DIYer.
 
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