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Engine 1991 - What does a normal idle suppose to sound like on OEM 5.0 ?

  • Thread starter Thread starter MrPerfect2
  • Start date Start date Jul 23, 2019

MrPerfect2

5 Year Member
Jul 23, 2019
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Jul 23, 2019
#1
  • Jul 23, 2019
  • #1
I am Not sure if my timing is set too high . New plugs , wires , rotor , cap , coil - seems to idle fine just has a slight miss every 10 seconds or so - runs great on WOT - I have been driving mostly newer cars for along time and used to a smooth steady idle - does the stock cam on these cars produce more of a non smooth idle ? I am not a total gear head , but I still do a lot of basic repairs myself ( plugs , brakes , sensor changes, gauges )
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
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Jul 23, 2019
#2
  • Jul 23, 2019
  • #2
The stock 5.0 is pretty smooth.
what is your timing set at?
 

MrPerfect2

5 Year Member
Jul 23, 2019
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Jul 23, 2019
#3
  • Jul 23, 2019
  • #3
I have no idea what it is set at - aside from using a light ( which I don’t have ) any other symptoms of too advanced timing ? It does idle smooth , just has a very slight miss feel every so often 10 seconds at idle .
 

Blown88GT

Founding Member
Nov 13, 1999
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Jul 23, 2019
#4
  • Jul 23, 2019
  • #4
Smooth, steady idle is probably not timing related. What year, i.e. MAF or SD?
Vacuum leak will cause an unsteady idle on any vehicle, old or new.
A miss at idle could be many things.
 
Last edited: Jul 23, 2019

MrPerfect2

5 Year Member
Jul 23, 2019
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Washington DC
Jul 23, 2019
#5
  • Jul 23, 2019
  • #5
I know my question is kinda vague - btw it is MAF - what sensors are important and help on these cars with air / fuel mix ?
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,958
10,600
203
polk county florida
Jul 23, 2019
#6
  • Jul 23, 2019
  • #6
Basically all of them.
if you feel the need to check things out on your car go here:

Help me create the "Surging Idle Checklist"

Updated 26-Oct-2019 to clarify creeping idle RPM increase as the car is being driven. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of...
forums.stangnet.com
It shows you how to check for codes and what the sensors are for and the operating range.
 

MrPerfect2

5 Year Member
Jul 23, 2019
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Washington DC
Jul 24, 2019
#7
  • Jul 24, 2019
  • #7
That is perfect info I was looking for - thanks ! I will do some vacuum hose inspection / change and various sensor inspections / change
 

Mstng93SSP

You have a nice rear end there Dave.
15 Year Member
Nov 29, 1999
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Jul 26, 2019
#8
  • Jul 26, 2019
  • #8
Make sure your firing order is correct, it's easy to cross up plug wire #5 and #6 if you have replaced plugs or wires recently. Then, set your timing with a timing light. If you don't have one I'm sure you could borrow one somewhere. A timing light is the only correct way to set the timing.
 
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