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Need Help,engine started missing once it warms up.

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Old 11-12-2005, 02:13 PM   #1
RodGT35th
 
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Default Need Help,engine started missing once it warms up.

Had my 1999 GT 1 1/2 years now, 61000 miles, 5 speed. Anyway I baby this car, premium gas etc. Yesterday after it warmed up all of a sudden at low RPM under load only, the engine starts missing or skipping during acceleration. Once rpms are fairly high, most of the skipping/missing quits. I added a can of SEAFOAM and another tank of premium. I am getting NO check engine light. Plugs are still looking fine,don't believe they are fouling. Engine does hesitate slightly when you are in neutral and go to WOT. Sort of bogs out slightly,only slightly. However as stated earlier, under load only from 1 to 3000 RPM missing and skipping throughout acceleration.
Went out this morning took for her a spin. No problem while engine is cold. It ran fine, I thought the problem was gone. Then once it warmed up, BAM, it started again. HELP!!! Suggestions please.
I appreciate it.
Rod
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Old 11-12-2005, 03:16 PM   #2
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Default RE: Need Help,engine started missing once it warms up.

may be a coil pack goin bad.
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Old 11-12-2005, 05:08 PM   #3
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Default RE: Need Help,engine started missing once it warms up.

i agree on those coil packs. it sounds like an electronic issue.
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Old 11-12-2005, 06:27 PM   #4
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Default RE: Need Help,engine started missing once it warms up.

You are probably still showing a code. It takes confirmed hard code to throw on the CEL. Sounds like an ignition problem, especially with your mileage and the symptoms you described. If they are original plugs, change them.

New coil pack will run about $65. They came down on price here recently.
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Old 11-12-2005, 08:15 PM   #5
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Default RE: Need Help,engine started missing once it warms up.

If its a coil pack, would it show up as a code? Otherwise...1 of 8 to find!
I agree with you on the codes without CEL on. My old pre 96 code reader will show codes on my 93 ranger and 94 explorer without a CEL activation.
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Old 11-12-2005, 09:51 PM   #6
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Default RE: Need Help,engine started missing once it warms up.

If it's intermittent like you say, then it probably won't make a light come on.
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Old 11-12-2005, 10:12 PM   #7
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Default RE: Need Help,engine started missing once it warms up.

I was thinking more about the coil issue. If I'm not mistaken,at least as far as transformers and solenoids go. When and inductance device fails, it fails. So even though I too believe it's an electrical problem. I just don't know where to begin without a code. I cleaned my MAF sensor with electrical contact cleaner. I've got K&N filter on it. Had one on my 93 ranger for about 4 or 5 years. My MAF failed on my ranger and acted a lot like the Mustang. However I got a code light on my truck. I thinking those K&N filters get residual oil on the sensors??? Makes you wonder. I called Advance auto parts and asked them if they would hook up their code reader. They said not unless I was getting a check engine light.[:@] Thinking about going by and telling them it was on. Anyway I am still open to your comments Thank ya, Thank ya!
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Old 11-12-2005, 10:27 PM   #8
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Default RE: Need Help,engine started missing once it warms up.

i had a long *** thread on here awhile ago about my car doing that since i bought it. i did 1000 things to fix it.. i jus recentyl fixed it and i did the plug wires and coil packs in the same night then check all my replaced spark plugs and cleaned them up and one of them things worked cuz it runs perfect now. good luck with it
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Old 11-12-2005, 10:27 PM   #9
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Default RE: Need Help,engine started missing once it warms up.

I'd check the alternator and battery first. If you're battery is 'bout dead, then it may siphon off too much juice until the alternator is spinning very fast. Or, the alt may be going. This could explain why the problem goes away at higher rpm.

Also, I'd look at the IAT sensor. This could explain why the problem occurs after warm up.

Let us know what you find out. You can make us all a little smarter.
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Old 11-12-2005, 10:34 PM   #10
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Default RE: Need Help,engine started missing once it warms up.

BTW, there is no need for you to be using premium gas.
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Old 11-12-2005, 10:37 PM   #11
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Default RE: Need Help,engine started missing once it warms up.

I did have a look at the IAT sensor this morning. I cleaned it with a burst of contact cleaner(not that it would help that much if bad). You know I might better start with a plug job first. Who knows maybe a plug is heating up and fouling?? Anybody had that happen before?? I did find out one thing by chance. This morning I took a plug out. There was crap load of dirt under that boot(the coil boot). I didn't have a compressor to blow out that God awlful deep pit the plugs reside in! Man..thats the first time I've seen the plug well on a 4.6! About like a bottomless pit.[&o] Anyways, make sure you all blow them things out before removing old plugs.There was grit all in that thing.
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Old 11-13-2005, 04:53 AM   #12
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Default RE: Need Help,engine started missing once it warms up.

I agree the coils and plugs are probably bad but if you change them and still have the same problem check the throttle position sensor. I broke a wire on my tps while installing my cai and my car did the same thing.
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Old 11-13-2005, 09:38 AM   #13
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Default RE: Need Help,engine started missing once it warms up.

04BlueGT,

I am amazed at how wild your advice always seems to be. I mean totally off the wall ignorant.

I would like to know how a bad battery would make "the alternator spin very fast". At what point does it spin faster then it normally does. And being that the battery is nothing more then a reserve unit, how would it affect the ignition system. Think before you talk...or type rather.

Start your car and take your battery out...you can drive to town if needed.
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Old 11-13-2005, 09:47 AM   #14
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Default RE: Need Help,engine started missing once it warms up.

Rod,

There is really no way to diagnose this problem without hooking to a scanner or taking it to the dealer. Anything else will be lucky guess work. Considering that you have checked the obvious of course...pull the coils and check for any water,coolant in the plug holes, etc. More then likely you are showing a pending code for a cylinder misfire, which only a scanner would show under "pending codes". Even if you are not showing a pending code, Ford's diagnostic/drivability machine will show the level of resistance of each coil while under fire. This will definitely point you in the right direction if no codes are found.
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Old 11-13-2005, 10:21 AM   #15
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Default RE: Need Help,engine started missing once it warms up.

Quote:
ORIGINAL: Jglisson

04BlueGT,

I am amazed at how wild your advice always seems to be. I mean totally off the wall ignorant. What, are you stalking me?

I would like to know how a bad battery would make "the alternator spin very fast". At what point does it spin faster then it normally does. And being that the battery is nothing more then a reserve unit, how would it affect the ignition system. Think before you talk...or type rather.

Start your car and take your battery out...you can drive to town if needed. Maybe this would make more sense if you had correctly read my post?


I'd like to know how you graduated without the ability to read?

Its a small physics law thing. Increased RPMs of the motor will make the alt spin faster. Remember how he stated that the problem stopped at higher rpms? Reread the post before YOU type.

With over 20 years driving/wrench turning experience, I've seen a shorted battery drain enough power to cause electrical problems at low rpm. Twice.

Do I think that the problem is with the battery? No. Possible, but not likely. It is rather rare, especially with today's batteries.

Jglisson, I don't remember labeling myself as an expert at any point. Often, I refer folks to blueanglefightr, jdaniel, and code. When I learn something from you, I'll refer people your way also.

We all offer options and opinions. I won't suggest anything that will aggrevate or complicate, or otherwise place at risk, someone's problem or vehicle, or any component thereof.

Again, I do/did not portray myself as an expert in this area. I offer thoughts based upon personal experience and what I have learned here from those more knowledgeable.

And I'm getting a little tired of the juvenile behavoir I've seen portrayed on the forum. I'm not talking about your comments directed at me, but in general how certain boys feel the need to flame others for having a different opinion. Or encouraging others to behave irresponsibly with regard to driving and racing. There are some really cool people here who act all grown up, and then there are the others. Pick a category.

Yeah, I'm being a dick right now - how does it feel?
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Old 11-13-2005, 09:27 PM   #16
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Default RE: Need Help,engine started missing once it warms up.

Ok, I took it by Advance and got one of the guys to hook up his code reader. Nothing, no codes. Before I cranked the car today I used a Chiltons service manual and tested a few things . The TPI switch, IAT sensor,everything checked out according to my multimeter and the manual. When I got in the car everything was fine. Accelerated great, no skipping,nothing abnormal. Until I saw the Temp gauge begin to move up from cold to normal. Then like clockwork, missing and skipping. So bad my little boys 3 and 7 noticed it!
Could this be clutch slip? If it is why won't it do it when engine cold? The whole temp thing is what is blowing my mind. Do oxygen sensors not show a code when defective? Or could engine temp gauge cause this? The main thing is I'm not getting any codes at all! This sucks.
Rod
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Old 11-13-2005, 11:44 PM   #17
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Default RE: Need Help,engine started missing once it warms up.


Quote:
ORIGINAL: Jglisson

04BlueGT,

I am amazed at how wild your advice always seems to be. I mean totally off the wall ignorant.

I would like to know how a bad battery would make "the alternator spin very fast". At what point does it spin faster then it normally does. And being that the battery is nothing more then a reserve unit, how would it affect the ignition system. Think before you talk...or type rather.

Start your car and take your battery out...you can drive to town if needed.

Point taken, i would check the alternator but for completly different reasons.
Rod35th, have you noticed, if your battery light flickers when you get on it?
I had the exact same problem that your having, when the car was warmed up, it would skip or "miss" at low rpms when wot, but only when warmed up. Problem was that my intake had cracked right behind my alternator and was spraying a significant amount of water into the alternator causing a short that was make my batterlight flicker and for the car to miss. And i'm guessing it only did it when it was warm cause thats when your water system is most pressurized. It took me a while to find the crack cause it was right behind the alternator and hard to see.

If thats not it, check coil packs. it would have a similar miss effect. a cracked intake can also cause that cause water will short out those packs.

Hope this all helps
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Old 11-14-2005, 12:44 AM   #18
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Default RE: Need Help,engine started missing once it warms up.

Phirantes,

Given the common problem with the intakes, your problem may turn into a common one with the Mustang.
I would hope Rod would have noticed a coolant smell or seen coolant when he was looking around under the hood.

My intake cracked at the t-stat housing, which is a little less common I hear.


Rod,

Just cough up the $75 and have the stealer run a diagnosis on it. Or, if you know anyone at the dealership they may hook you up after hours for a better price. Either way, it could be anything. Automotive repair is not a basic science like many people think. But still, you are more then likely looking at a coil/ignitio problem.

Couple of questions...does it misfire at idle when warmed up?

What rpms do you get a misfire?

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Old 11-14-2005, 12:48 AM   #19
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Default RE: Need Help,engine started missing once it warms up.

Blue04,

I dont' give a crap how long you been turning wrenches...you prove you don't know Fords, little alone Mustangs.

If you don't like the forum...click that little X at the top right corner of your screen...problem solved.
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Old 11-14-2005, 01:18 AM   #20
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Default RE: Need Help,engine started missing once it warms up.

Well guys I've heard of the intake recall issue and the thought of cracked manifold has crossed my mind. I looked that engine all over today, dry as a bone.
Tell me, a slipping clutch would slip when cold too right? The motor sounds fine when in neutral and revving. It's only when at low RPM under load when warm is it an issue. The lower the RPM and higher load such as an uphill grade is when you feel the most. In fact I even went out on some side streets and started off in second. Really bad then until you get up past 2500 to 3000 RPM then fairly skip free. I guess it's dealership time. Dang it I pride myself on figuring stuff out and not going there. I know they over charge for everything. Looks like this one might be over my head. You know I believe the auto makers want it to be more and more difficult to diagnose problems. I've got a 62 Ford Galaxie(my first car by the way, had it since 1984)with a 352 FE big block. Man that things a piece a cake to fix. Look at image attached of my rides:-)
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Old 11-14-2005, 01:18 AM
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