Possible msd ignition issues?

Awhile back I put a digital 6 box in my truck.
Everything was fine until last month when the 2 step stopped working correctly while on the trans brake. It quit chattering for lack of a better word. My rpm's would still stop where it was set at though.
The last 2 races my 1/4 mile ET and mph have been off by 2-3 tenths and 4mph. I just figured it to be the hot humid weather.
This past Saturday while in the staging lane for qualifying my tach jumped from idle rpm to 4000rpm a few times and the shift light flashed several times.
When the qualifying pass was over I checked the max rpm on the tach and it went to 7000rpm (6500 is normal). I erased it and started the engine again, this time it was only idled. The recall went past 9000 rpm.
I did try a different coil for 2nd round qualifying. the recall rpm seemed right but the performance was still off.

Do you guys think the digital 6 box is my problem or is it something else??

Mike

Sunday I swapped out the digital 6 for my old 6al and 2 step.
I won't be able to try it out til Saturday at the races.
The tach seems to be working ok now.

Randy, I haven't checked the ohms on the wires since late last year.
I had thought about getting new ones but they checked out good
Thanks, I'll have to check them again.
Mike

Thanks again Randy!!
I tried calling the msd tech line today and must have put the wrong # in my cell phone.
I called some real estate office somewhere .
mike

Well I guess the ignition box was where I had my issues.
I raced today and the truck ran more consistant than it has all year .
Today was the finish of a rainout from last Saturday.
My first pass was a test pass and it went 12.04 at 109mph.
I went 3 rounds and ended up with the win. All 3 were 12.07 at 109mph.
New spark plug wires are going on before my next race just in case today was a fluke.

Thanks for the help guys
mike