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bad idle/misfire? after new spark plugs and wires
03-27-2009, 08:24 PM
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bad idle/misfire? after new spark plugs and wires I just installed new spark plugs (NGK TR6's .35 gap) and MSD wires.
After starting the car I noticed the car had a weak idle and engine just overall felt like it was running rough. When I put it in reverse to back out it almost died but then the idle came back up. Almost feels like there's a misfire or dead cylinder.
The spark plugs I pulled out were pretty wore out ac delco's (.67 gap) one had some oil on it. Also the air hose that goes into the passenger side manifolds had NO gasket at all, so I used some RTV sealant.
What do I need to check? What could have possibly gone wrong?
And thanks for any and all help.
After starting the car I noticed the car had a weak idle and engine just overall felt like it was running rough. When I put it in reverse to back out it almost died but then the idle came back up. Almost feels like there's a misfire or dead cylinder.
The spark plugs I pulled out were pretty wore out ac delco's (.67 gap) one had some oil on it. Also the air hose that goes into the passenger side manifolds had NO gasket at all, so I used some RTV sealant.
What do I need to check? What could have possibly gone wrong?
And thanks for any and all help.
03-27-2009, 08:49 PM
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I would start be re-checking all the plug wires to make sure they are connected properly. I'm not sure what air hose you're referring to but I hope you did not use RTV directly on the exhaust manifold. That won't do anything but make a big mess
03-27-2009, 08:50 PM
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.67 gap is pretty big. i just did new plugs and wires and the plugs i got were .40 gap. I've heard that they changed the gap size because a lot of people were complaining about a rough idle. but not sure. also you could try cleaning your throttle body. seemed to help mine a little. good luck
03-27-2009, 09:18 PM
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.67 gap is pretty big. i just did new plugs and wires and the plugs i got were .40 gap. I've heard that they changed the gap size because a lot of people were complaining about a rough idle. but not sure. also you could try cleaning your throttle body. seemed to help mine a little. good luck
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03-28-2009, 07:07 PM
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The oil was unburnt and I didn't see any oil on the NGK plug that I just took out. (in the same cylinder that had oil before)
I had time to do the drivers side spark plugs (new acdelco iridium's) before it got dark. The car isn't misfiring anymore, so one of those NGK plugs on the drivers side must have been bad or something?
I'm going to finish the passengers side plugs tomorrow, i'll post if it runs any different after that.
*Update
All the new acdelco's fixed the problem, used a friends live scanner tool and checked for misfires 109 stored in memory from the NGKs, and no current misfires from the new plugs.
I had time to do the drivers side spark plugs (new acdelco iridium's) before it got dark. The car isn't misfiring anymore, so one of those NGK plugs on the drivers side must have been bad or something?
I'm going to finish the passengers side plugs tomorrow, i'll post if it runs any different after that.
*Update
All the new acdelco's fixed the problem, used a friends live scanner tool and checked for misfires 109 stored in memory from the NGKs, and no current misfires from the new plugs.
Last edited by epox4life; 03-31-2009 at 07:31 AM.
07-21-2010, 01:30 PM
#15
I have the same problem but put new ngk t55 plugs 4kmiles, & on Monday 7-19-10 I cleaned maf, tb, & I put new fuel filter, msd wires & still idles @ 500-650 my car been park since febuary on & off still has misfire #3 I swap coils & no change, should I try acdelco plugs?
Last edited by ls1jorge; 07-21-2010 at 01:32 PM. Reason: .
01-05-2011, 08:36 PM
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I know this is an older post, I have this same problem, I have triedt he same things as you my car runs rough at idle and misfires at about 4500 rpm did you ever figure out your problem?
