2005 xc70 misfire, cylinders 2 and 4

mrscullini · Post by **mrscullini** » 12 Jan 2015, 08:24

draser wrote:Short term fuel trim -STFT, long term - LTFT. Can you inspect coil connector for 2, 4 to make sure wiring is good condition, conn clean - maybe spray some cleaner?

some fuel trim numbers, ambient temp is about 35 degrees F.

this was at start up, cold engine

longft1= 2.3
shortft1= -7.0
shrtftb1s2= 99.2

operating temp of 90 deg C and RPM ~650

longft1= 3.9 (holding steady)
shortft1= -3.1 to 3.1 (this range seemed to get narrower as motor warmed)
shrtftb1s2= 99.2 (holding steady)

draser · Post by **draser** » 12 Jan 2015, 08:53

Short one is normal, single digits bouncing around 0. Long is okay, I'd keep an eye on it when it's acting up. Double digit positive usually means air leak.

mrscullini · Post by **mrscullini** » 12 Jan 2015, 08:56

draser wrote:Short one is normal, single digits bouncing around 0. Long is okay, I'd keep an eye on it when it's acting up. Double digit positive usually means air leak.

great draser, thanks so much for all the insight, much appreciated!

one other question, have you heard/experienced a misfire just being a "hiccup" of some sort?

draser · Post by **draser** » 12 Jan 2015, 09:16

I can't say I have, but I'm a relatively new Volvo owner. This forum will be a better source of info.