Took Ruf DME out, diagnosis appreciated

[D Hanson]

I was starting to get a little over run I guess or decelleration type of light back fires after first gear alot and, when cold, I noticed the car started hestitating a little under load in second gear. It got to where it would spit, and stutter a bit. Once I run up the RPMs though, it was okay.

Put the stock DME back in and the hesitation when cold is gone and only has a very slight back fire after first once if you run up the revs to about 5k RPMs when cold in first. No more back fire or spitting after that.

Any ideas. I did not have any of these types of problems when I first installed the RUF DME. I feel like the car was running much leaner with the Ruf DME. The stock DME seems a little smoother and quieter if that is possible.

I am over due for the valve check after the rebuild. Could I have a valve slightly out of adjustment causing the cold start backfire.

What would cause the hestitation and literal spitting sound when under load in second gear when cold.