So I thought i had the misfires taken care of..
Brief background. Last fall while on a 1500 mile run I lost an o2 sensor, ran it for the trip. Got home and replaced both upstream sensors. all good. Then started with misfires on cyl 3, 5 and on occasion cyl 7. but only when driving faster than 50mph under 50 mph no issues, no codes nothing. So I went the route of coil packs. all seemed well. about 2 weeks ago threw the same codes. 1300, 1303, 1305. changed out the plugs with new bosch, exact replacements. Today again while driving over 60 same codes. under 55 no issues over 60 codes thrown... really getting frustrated, no other issues, no coolant loss no over heating no rough running or idle... any thoughts anyone anyone...

 

Does that mean you replaced them, or just tested them?

 

changed out the plugs with new bosch, exact replacements.

meaning new plugs replaced with the same type, brand, etc...

 

I put "So I went the route of coil packs" in bold, you said you changed out the plugs so I wasn't questioning that.

 

sorry mis-read.
Yes replaced coil packs..

 

And you gapped all the plugs properly?

 

not needed with the Bosch plugs.

 

negative...it's needed with any plug. Not to change the gap, but to check the gap. I ordered 5 pre-gapped plugs for my S60R recently and due to handling the variance was as much as .005!

 

Electrode gap is factory set
Provides ease of installation - never requires adjustment

straight from Bosch. Now even if I am wrong on this, which is always a possibility, why would these codes be thrown regardless of what I have replaced, as I mentioned. The chances of the plugs in cylinder 3 and 5 being equally off are beyond astronomical. The plugs that were in there had close to 20k on them with no issues, until after I swapped out the 2 upstream O2 sensors, and only over 50-60 mph, So the issue of a gap issue i must say is not on my list of possibilities.

 

Well anything is possible, it's good to rule everything out. Have you ever noticed a misfire on cyl. 1? Wonder if it's a defective coil pack on the odd side. Though it seems like you'd have rough idle and accel if the coil was bad.