95 Mustang GT idle issues

[Coyote12387]

Ok, will do next evening I have free. I pulled one of them earlier and it looked brand new, didn’t notice anything abnormal with it. Front driver side

 

[ttocs]

If its running rich the plug will be black. The richer it runs the blacker the plug.

 

[Coyote12387]

Well this plug wasn’t black at all, but I only pulled one. Very small amount of oil on it near the top, but I’m sure that’s just from an old Valve gasket.

 

[Coyote12387]

 

[Coyote12387]

Cylinder 4

 

[07GtS197]

You need to pull all of them. If its a stuck injector youll only be able to find it by looking at all the cylinders.


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[ttocs]

you can also diagnose individual cylinder problems if you have a temp gun. Start the car cold and then after a min or two check the heat of the individual cylinder headers. I found my injector problems like this because the cylinders with problems were colder then the others.

 

[Coyote12387]

I’m going to pull them all, just didn’t get around to it. Hmmmm, would have never thought of using a temp gun.

 

[Coyote12387]

Couldn’t I just unplug the injectors one at a time and listen for a change? That’s what another person suggested.

 

[07GtS197]

You could but reading plugs is very basic but can diagnose a lot. No offense but youre making things harder than they have to be. Yes you can unplug each injector one by one but itll only help you if you had a dead injector. If you were to pull the plug it will tell you exactly whats going on in each cylinder. Dont be afraid of pulling the plugs and reading them, its a very old but useful means of diagnosing various problems but has become overlooked nowadays.


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[Coyote12387]

Oh I know that’s easier, I was already going to pull the plugs before doing anything else.

 

[Coyote12387]

 

[07GtS197]

Did you gap them before you installed them? It looks like cylinder 1 has too little gap. How many miles are on those plugs? It looks like whatever the issue is isnt very serious or you’d get different results. I’d recommend opening the gap to .054, checking all the others, and reinstall.


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[Coyote12387]

Plugs have around 1,000 miles on them. Yes I gapped them, but I see what you’re saying with cylinder 1

 

[evilcw311]

Yeah that gap on 1 is way to small.


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[Coyote12387]

Gaping #1 seemed to have smoothed out the idle. There is still a slight miss at idle though. You can feel it in the exhaust

 

[evilcw311]

Gaping #1 seemed to have smoothed out the idle. There is still a slight miss at idle though. You can feel it in the exhaust

At least we’re making a little bit of progress one step at a time through elimination.


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[Coyote12387]

very true, I appreciate your help! It’s odd to me that I can feel a miss at idle, but not when driving or accelerating.

 

[evilcw311]

very true, I appreciate your help! It’s odd to me that I can feel a miss at idle, but not when driving or accelerating.

That could very well be a fuel injector that’s lightly clogged.


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[Coyote12387]

I’ll check the injectors tomorrow. Good news is I took all the plugs out and made sure they were at .54. While doing that I found that cylinder 8 plug had worked itself lose. Corrected that and the car is idling much smoother now.