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Engine "miss" at idle by trivet
Started on: 06-11-2015 01:14 PM
Replies: 8 (259 views)
Last post by: fierosound on 06-13-2015 05:31 PM
trivet
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Report this Post06-11-2015 01:14 PM Click Here to See the Profile for trivetClick Here to Email trivetSend a Private Message to trivetEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hi all,

My 87 GT with about 85K will occasional "miss" or hesitate at idle. Accelerates and drives perfectly, it's just at idle. Never stalled, but it seems to be getting worse.
I have replaced all plugs and wires, distributor (cap and rotor) late last year (seemed to run a lot better right after that) but it's doing it again, same as before.

Any suggestions on where to start looking?

Thanks in advance for any help!

------------------
Tim
'87 GT
Med Red Metallic
81K miles
Bay City, MI

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Gall757
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Report this Post06-11-2015 01:27 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Pull and re-connect the plugs on the ICM, and the pick-up coil. Test the ignition coil and the pickup coil.....it may be a ground problem too.

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Report this Post06-11-2015 01:54 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:

Pull and re-connect the plugs on the ICM, and the pick-up coil. Test the ignition coil and the pickup coil.....it may be a ground problem too.



x2

also no check engine light huh?

[This message has been edited by 2.5 (edited 06-11-2015).]

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Report this Post06-12-2015 06:44 AM Click Here to See the Profile for QCMANAGERClick Here to Email QCMANAGERSend a Private Message to QCMANAGEREdit/Delete MessageReply w/QuoteDirect Link to This Post
Try the idle air control valve - that fixed mine.

I would also have the fuel delivery system cleaned.

Hope this helps.

[This message has been edited by QCMANAGER (edited 06-12-2015).]

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trivet
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Report this Post06-12-2015 08:42 AM Click Here to See the Profile for trivetClick Here to Email trivetSend a Private Message to trivetEdit/Delete MessageReply w/QuoteDirect Link to This Post
I really appreciate the suggestions, I'll dig into it some more this weekend.

I have no check engine light codes, and I'm wondering if it might be a ground issue. If so, what would be the solution?

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Tim
'87 GT
Med Red Metallic
85K miles
Bay City, MI

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Report this Post06-12-2015 09:22 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trivet:

and I'm wondering if it might be a ground issue. If so, what would be the solution?



2 things:

1.

Disconnect and clean existing grounds. See the Ogre's cave (Wire Service) if you don't know where they are.

2.

EVERYONE with a V6, please read

[This message has been edited by Gall757 (edited 06-12-2015).]

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Report this Post06-12-2015 09:23 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Check all the grounds in the engine area for good connection.

-

"The 4 main ground ties and positive leads.
#1. (-)Braided block to body ground, deck lid hinge. The main braided strap is critical.
#2. (-)Trans to body. The trans to body is a backup.
#3. (-)Battery to body. Battery (-)post to tray.
#4. (-)Battery to engine block. The big batt cable (-)post to bolt on engine hoist hook.

Positive leads (+)

#5. (+)Battery to starter
#6. (+)Battery to main terminal below C500.
#7. (+)Alternator feed to main terminal below C500.

NOTE. The Ogre has mentioned that if #7 is bad, you will get large voltage drops under load just like a bad ground. We all know what bad grounds do to a Fiero's electrical systems!"
http://www.fiero.nl/forum/A...041015-2-052227.html

also
http://www.fiero.nl/forum/A...090219-2-082708.html
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trivet
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Report this Post06-12-2015 12:37 PM Click Here to See the Profile for trivetClick Here to Email trivetSend a Private Message to trivetEdit/Delete MessageReply w/QuoteDirect Link to This Post
Wow! Thanks for the great links - I'll be checking this first, as I have some of the other symptoms of bad ground (grounds? Grounding?)

LOVE this forum!!!
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Report this Post06-13-2015 05:31 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have the metal heat shields on the spark plug boots?
Have a look at them in the dark with engine running.

If you see arcing from the shields to the head - take them off.

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Calgary time/temp

3.4L Supercharged 87 GT Click me
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