First, the car has new spark plugs, good tune from Kevin at UMW, new 997 coil-packs, new O2 sensors, new MAF.

1) When the engine is not up-to temp (180+), when shifting, there is a slight hesitation unless I shift a little slower then normal. This goes away completely when warmed up. I changed all the above in an attempt to fix this as recommended by Kevin but it continues. I have just been adjusting my shifting but would like to figure it out. Not sure if I can data-log anything with the Durametric during shifts ti find the problem.

2) When warmed up and I come to a stop, the voltage & idle will for an instant dip down to like mid 12s then bounce immediately back up-to high 13s where it stays. It only does this once of twice when driving over a course of maybe 30+ stops.

Boost holds a steady 1 bar and car runs great, no CEL or codes being tripped.

 

do you have a short shift? i was told when i put mine in that it would feel stiff until the car warmed up.. the other issue sounds like a alternator , voltage reg, going bad...

 

Factory shifter. Its not an issue with the actual shifting, its actually a hesitation right after the shift.

 

Maybe try a throttle body service. They get sticky and it can't hurt.

 

I wouldn't worry about the 1st problem; you say it goes away after the car is warm.. the second one sounds like what i said, not sure with these cars...

 

I 2nd the throttle body service... I've seen the throttle body get pretty gunked up and they start sticking causing the motor to do some weird stuff. You can do it yourself.

 

First I suggest not do this over the net (you'll get 10K things that have nothing to do with your issue). Call Kevin and explain. It may be as simple as the vario cam hesitation or a minor adjustment to the tune, etc...but talk to him (your tuner).

 

Kevin already suggested Plugs, coilpacks, MAF and O2s as the solution. It did it with the factory tune as well.

 

Are you running a stock clutch slave cylinder? The reason I ask is because the idle dip that happens I read on one occasion was caused by a failing 996tt slave cylinder. Not sure if this is the case, but something to keep in mind.

 

I am running the stock clutch setup. How would that cause an idle dip for a brief moment?

 

Not sure. I just know that a guy posted here about it and said that it went away when the slave was replaced. Seems to be a fairly common issue.