Grand Am 3.1 Cyl. Misfire on #3 Cylinder

Tiny
CHRISTI992
  • MEMBER
  • PONTIAC GRAND AM
My check engine light came on last week and it started cutting out. I took it to a place and had a computer on it and it said misfire on #3 cylinder. I replaced spark plug wires and plugs. I also replaced the ignition coil. What else could I fix?
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Wednesday, March 21st, 2007 AT 6:59 PM

24 Replies

Tiny
KIN CHAN
  • MEMBER
Hmmm. Let me think.I remember I answer similar questions about 10 times on this site. Do u mean what other parts u can replace in order to repair this problem?
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Wednesday, March 21st, 2007 AT 11:06 PM
Tiny
CHRISTI992
  • MEMBER
Yes that is what I mean.
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Thursday, March 22nd, 2007 AT 9:07 AM
Tiny
MMPRINCE3000
  • MEMBER
Have a compression check done on all cylinders. If #3 has low or no compression, you need to find out why.
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Thursday, March 22nd, 2007 AT 9:12 AM
Tiny
KIN CHAN
  • MEMBER
Are u crying yet.I know I am.
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Thursday, March 22nd, 2007 AT 11:48 AM
Tiny
CHRISTI992
  • MEMBER
I also have been having problems with it dying suddenly. It is only after I have been driving for a while. It doesnt get hot or anything, it just dies. Then if I let it sit there for a while it starts and runs just fine. I think it is my fuel pump. Would this have anything to do with my other problems?
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Thursday, March 22nd, 2007 AT 12:01 PM
Tiny
KIN CHAN
  • MEMBER
Okay. How bout this. Tell me what year and model 1st. And we'll try it from there?. Agree?

Ps: the 'are u crying?' Is for mmprince. Not u christi.
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Thursday, March 22nd, 2007 AT 4:04 PM
Tiny
MMPRINCE3000
  • MEMBER
? Maybe easier to say what you mean rather than some vauge reference.
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Thursday, March 22nd, 2007 AT 5:24 PM
Tiny
KIN CHAN
  • MEMBER
Aint u crying as I am. When some1 tryin to swap a part to fix the problem as shot gun to roll the dice. Simple enuff?
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Thursday, March 22nd, 2007 AT 5:51 PM
Tiny
CHRISTI992
  • MEMBER
I have a 98 Pontiac Grand Am SE
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Thursday, March 22nd, 2007 AT 7:28 PM
Tiny
SERVICE WRITER
  • EXPERT
Lol.
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Thursday, March 22nd, 2007 AT 8:11 PM
Tiny
MMPRINCE3000
  • MEMBER
Better.
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Thursday, March 22nd, 2007 AT 8:31 PM
Tiny
KIN CHAN
  • MEMBER
I mean come on techs. Yeah I mean both of u mmprince and service writer. Especially service writer. Don't just roll around the floor.I know u have enugg 3.1 roll thru ur shop with single cylinder misfire. Whats next. Remember ur mission here.I think I should keep my big mouth open with time delay this time. Hey mmprince. Aint that 3.1 is the same as a malibu.I think its kinda hard to pull plugs out when engine is warm then block iac and other vac outlet and do the static, running and snap compression. MORE INPUTS GUYS!
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Thursday, March 22nd, 2007 AT 10:08 PM
Tiny
SERVICE WRITER
  • EXPERT
I 'll add my 2 cents for what it's worth.
Since we know the plugs and wires have been changed and we are "assuming" the light is still on and the drive cycles are complete, my suspicious is a bad intake manifold gasket or injector problem.

The earlier 3.1 motors more often than not would be moreso related to injectors, that latter ones as this as more so related to intake manifold gasket troubles.

Pull off the oil cap and check for any signs of moisture (yellowish substance). Check the areas around the intake for signs of seapage. Anything?
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Friday, March 23rd, 2007 AT 5:10 AM
Tiny
MMPRINCE3000
  • MEMBER
I'll add 2.5 cents.
It is not unreasonable, given OBD-II said he had a number of misfires in #3, to change plugs and maybe wires.
I would have looked at the plug and measured resistance in the wire first.
Since they have been replaced and it is still missing, I would at least check compression on #3 to eliminate a mechanical problem, or verify one.
Could be a gasket/injector problem as Service Writer mentioned. A cooling system pressure/noid test would verify this.
Normally on a cylinder misfire, I would check spark on that cylinder with a plug tester and use a noid light on the injector, then go to compression test, then a cooling system pressure test.

The main reason I would follow this procedure is that it makes no sense to throw parts at a problem, you may get lucky and hit it the first time, then again, it may be the last part you buy.

KC eluded to this in the shotgun analogy, I agree.

If you are new to working on a car, the best investment you can make is a factory service manual, or at least a Haynes manual.

As an example I am trying to find out why the cooling fans on a 1991 Corolla are not working, the factory manual has some 42 seperate steps to try and isolate the problem. I'll start with the first step this weekend (fuses) and go from there.

I must say that is far easier (obviously) to diagnose a problem like this when you have the car in front of you than over an internet forum.

I think our mission is to give information based on our experience. It also is our responsibility to tell a forum member to "punt", and take the car to a professional. I have done as much in the past, myself.
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Friday, March 23rd, 2007 AT 8:21 AM
Tiny
KIN CHAN
  • MEMBER
Hey. Both tech. Are u guys on commissions?
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Friday, March 23rd, 2007 AT 11:46 AM
Tiny
MMPRINCE3000
  • MEMBER
No, but many people here are not concerned about time. They are doing this as a hobby or to save the labor costs associated with dealerships.
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Friday, March 23rd, 2007 AT 11:57 AM
Tiny
SERVICE WRITER
  • EXPERT
Kin-
You have been a great help on this post. If you have somthing to say then say it. If you don't like someone's opinion, then at the very least give yours. Your obviously skilled, just not in communication.
Is our "mission" (your words)

to be a "verbal sniper"?

I have yet to hear from you to answer this post, if you know it, then say it.

Yeeesh!
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Friday, March 23rd, 2007 AT 7:40 PM
Tiny
KIN CHAN
  • MEMBER
I appreciate the honest opinion. And the over estimated compliments.I know and believe u all way complicated me. Thanx service writer.
Hey guys lets get serious. By no means from the bottom of my heart that in anyway shape, forms or expression that I being sarcastic nor trying to be funny. But don't u guys think that it is kinda hard to abandon basic internal combustion engine principles, professional tools and application and equated it with very primitive uncertain hardware for most average car owner so they can verify a problem? For example. I pull my modis scope the primary ignition on a good cylinder and #3 cyl. Also same on the injectors.I can pretty much wrap it up in 10 minutes. But now I have to come up with tools or hardware that they can easily get their hands on with a striaght forward result. Cuz waveform takes time from training and experience. Agree?. As for compression.I aint even pulling plugs out.I'm lazy.I rather use a dual trace scope.1 for #1 injector and the other channel with a high amp probe. Disable cam and crank sensor(load factors) and see if the amperage draw to conclude a mechanical bad cylinder. Intake coolant leak can be a 5 minute pressure tester and smoke machine for verification. But the challenge o is I can't tell most people here to do this. Which to me is kinda challenging. Cuz I have to come up with very primitive hardware which perfectly work with a particular system in order to nail down a problem. Let me think. Give me till tomorrow morning i'll come up with something. Don't go away guys.I wanna hear ur opinion if this work or not.----> To be continue

PS: hey we gotta get back to christi. Cuz this discussion started with a p0303 misfire. Wandering off to a moderator opinions session should be sometimes somewhere in a 2carpros moderator party
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Friday, March 23rd, 2007 AT 7:49 PM
Tiny
KIN CHAN
  • MEMBER
Okay tech. Chk this out
-- in this case we have to ask some very important question and set our own flow charts. Cuz we are dealing with rocks and stones against guns and bullets ( low tech against high tech) with limited resources of testing equipment and knowledges.
1.) What are our objectives?
--> figure out why #3 cyl. Is misfire
2.) What tools we have?
--> anything we can get our hands on under $20 or free
3.) What kinda misfire we are chasing?
Lean or rich misfire?
Density misfire?
Mechanical misfire?
Electrica(ignition) misfire?
Signal or trigger type?
I'm not at the shop so no acess to alldata. So I wanna assume 98' grand prix have a map sensor or else I'll substitue it with a vacuum gage ( under $20)
solution 1.)
idle & pwr brake & observe the value of map sensor or watch the vac. Gage.I wanna see if normal manifold vac value by looking at voltage vs vac (map sensor). If I get a normal steady value I know it is not mechanical(ie. Wiped cam, bad rings. Etc)
2nd - I'll verify the lean or rich density misfire by introducing a vac or propane @ idle and underload and see if the chk engine lite goes away or just feel if the cars drives better becuz I wanna to know if this is a true problem cause by fuel ctrl or not --> if I have positive result -->i'm gonna swap injectors(limited budget still hold the lines for not swapping parts but upon verification) and observe if the misfire move to another cylinder(visit auto zone again to chk codes)
3rd - I'll swap the coil on #3 cyl. And do exactly the same as injectors swaps and look for misfire occur on another cyl.
Actually if time is a big concern. I can just spend under $100 buy one of these cheap basic scanner that they sell here online and just look at the fuel trim if I have some big numbers change on fuel trim both idle and under load. If I have big number I know more likely it is a fuel ctrl problem not mechanical. And also watching short term fuel trim can tell me intake gasket leak or vac leak. Probably map sensor and total fuel trim to verfy a coolant or vac problem on the intake runners, egr. Etc.)
if any one of the above have no results. Now I know pwr and grd is the last thing I haven't lok at. Well max/min on an volt meter. Look up wiring diagram where's the pwr and grd for ignition and injectors.I nail a p0301 on a ford when every1 said it is the coil cuz it was a 99% late model triton mtrs pattern failure. Hehh heh. Not this case. It was bad injectors grd and it kept moving to different cylinders.
Well what u say guys?
Low tech against high tech - > heee hawww
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Saturday, March 24th, 2007 AT 3:56 AM
Tiny
SERVICE WRITER
  • EXPERT
You are methodical and logical. The last answers bring this full circle. I can better appreciate the "commission" comment now. Frankly, you were driving me crazy getting to this point.

You are also right about this not being the place to discuss this and I will start a post in the Mod section as to not muddy this up any worse.

Grasshopper
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Saturday, March 24th, 2007 AT 6:05 AM

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