New Spark Plugs Now Miss?

[1gDSMike]

I searched forever to find nothing, some similar but not exact. Simple question really.
New plugs, NGK6es, gapped right to .028 with wire gauge not ramp style. It's only when i do new plugs it misses at idle for a week or so?? car is stock besides a test pipe and k&n.

 

[Defiant]

How old are the wires?

 

[1gDSMike]

Couple months if that. It's only when I put new ones in. A few weeks or so will pass and it stops missing at idle.

 

[chico904]

You meant NGK BPR6es not NGK6es right?

 

[1gDSMike]

Yes yes, my bad. BPR6ES

 

[my dreamt dsm]

Is it the r6es or r7es for a stockish gst?

 

[jholmes]

Kind of a long chain of events but I'm going to go ahead and say that the ECU is compensating for a rich mixture (result of misfires) by leaning everything out causing further problems. Once the plugs have been changed it takes however many OBD cycles to begin adjusting the fuel trims which is the time when the car begins to run well again and the period prior to this being the time when there are new, properly gapped, plugs that are misfiring. As to the cause of the initial misfires, I haven't heard of many DSM ignition coils going bad but that could be the case. First thing I would check is grounds and plug wires. I don't have an FSM in front of me, but I'm sure there's a good flow chart to follow with a multimeter to test the ignition components. Good luck with everything and let us know how it works out for you.

 

[1gDSMike]

Yes this weekend I'm going to be getting a logger, and also check every sensor. I would think resetting the ecu would clear the old trims out?? The car runs like a dream. I bought it from the original guy who paid 16k for it back at Plymouth in 89.