[s-cars] Stumbling under acceleration.....probable boost leak?

[james McCarthy]

Sure sounds like a failing coil to me.  That sounds just like my experience when mine went out.  Intermittent stumble initially under hard acceleration progressively becoming more consistent and with less and less throttle application.  They can be tested relatively with a a "spark plug tester"

http://www.toolfetch.com/Category/Automotive/Spark_Testers/LIS50850.htm

Simply see which coil produces the weakest spark and replace.  I chose to do them all as I was at 120K and figured they were all on borrowed time.  

Alternatively if you're in CO might pop over to Apikol and pick up a 2.0 coil kit.

https://www.apikol.com/?#Products,Engine,21

Many folks seem very happy with this solution as it eliminated the POS and OEM coils for a fraction of the cost of replacing the all the OEM parts.  The 2.0 coils seem more robust that the 1.8 but I wouldn't expect them to last as long as the original equipment - especially in the Texas heat.

I may be wrong but I'm betting on the coils...
good luck

-jamie