Misfire (though no CEL) issues, problem or paranoia

[07-GXP]

So I have a 2007 GXP and have been experiencing misfires, primarily at idle, though at cruise as well, and I'm trying to determine if there is a real problem here.

I've had a dashhawk for about 6 months, and I notice that when I come to a stop light for example, I may see the "Total Misfires" PID hit up to 40+ (about 1 MF per sec) in cylinder 4...though I would say the average is about 10-16 over a 30-60sec period. The car does physically shudder when this is going on but is fine once I start moving.

If I'm cruising on the highway, I will occasionally see 2-4 TMF (total misfires) popup on the dashhawk from time to time. Again Cylinder 4 is the primary culprit, with the occasional blip from the others.

Now for some notes.
1) I do have the updated GM plugs, I swapped these out few months ago, did not effect the problem at hand.
2) At the time I changed the plugs, I also swapped the coil packs around, again no effect.
3) I only run 93 Octane in the car
4) Happens with both the stock ECU and tuned (pcm4less) ECU. Was occurring well before the tune.
5) I have never thrown a CEL or code for misfires.
6) Checked the grounds, from what I can tell they are ok.
7) Again, primarily only at idle or coasting

I've been to the dealer about 3 times for this over the last year or so. Everytime I'm told that this is normal for a turboed car and not to worry about it. I have a hard time buying into that, but the car does seem to run fine other than this so maybe I'm paranoid.

Since this is still going on, I figured I would ask what do you guys recommend or think of this?

I'm going to pull the plugs again this weekend just to have a peek, but since I've already changed them, I'm thinking that if this is a concern, it would have to be an injector...which I'm not eager to replace in my garage. Should I just take a picture of the daskhawk readout the next time I see a mess of misfires or forget about it until I see a CEL?

[gxp0514]

07-GXP,

I have the same "problem". With my Aeroforce Interceptor gauge, I get random misfires, mostly in #4 but also in other cylinders. My car doesn't shudder and only does it when lightly cruising or slowing down. No CEL and the counter resets itself to zero, if further misfires are not detected. According to the guys at Aeroforce and Wester's, this is normal and shouldn't worry about it. Makes you paranoid for sure...though...
Apprarently real problems will show hundreds of misfires in a short period of time. Hope this helps ease your mind.

[07-GXP]

Thanks Gxp, that does take a load off of my mind, particularly with Wester's input.

The shudders are pretty light, I probably wouldn't notice if I wasn't looking for it, my Wife never can tell, though that may not be saying much And like you said, it usually zero's out as soon as I start rolling again.