missing at idle

[2QMIKE]

98 Q45t,63000 m, 60000 services done--it started to have a miss at idle about 2000 miles ago-tried changing gas-water removal product-Taken to dealership twice-no codes!-tech even called infiniti hotline,only suggested BG service-had it done and seemed to fix it only statred again after 800 mile weekend trip!!! Help!!!Thanks,Mike

[PalmerWMD]

Mike ,

I'll switch this to online mehcnic for better response.

Fred...

[Q45tech]

Perform a STRESS POWER BALANCE TEST with Consult II.

Don't assume all techs are created equal..........my off the cuff guess is a bad ignition coil damaged when removed for plug change.OBD2 has all the parameters to find the problem just requires some difficult and time consumming testing and some brain power to know what they are seeing.

[2QMIKE]

Thanks to Q45tech-I had thought they was something in the ignition causing this because it is intermittent and only seems to do it at idle-mileage is off too-15-16 town-20 hwy.(80-85). I'll start with making sure all plugs are clean and gapped and coil connections clean. Service writer said could be coils-to the tune of $240 ea.x8+install=$2400+. I saw 90-96 coils on ebay sale for 120 for whole set-will this work on 98?Thanks again,Mike

[Q451990]

I'd say it's definately worth finding the culprit vs. swapping all of them. If you're good at DIY, you might find a junkyard coil and swap it one by one to see if you can isolate the problem. I'm not sure if the 97+ also uses the different coil connectors on cylinders 1&2 or not...you might have to buy two. Are the plugs easier to access on the 97+ than 90-96?

Heath

[DAEDALUS]

You might save a bit of labor by looking at the plugs. One that's more fouled up than the other 7 is the first cylinder I would replace the coil on.

[Q451990]

Great idea! I know that holds true for a bad injector, so maybe the coil too...

Heath