With the rear O2 sensors out of the way, it was a simple matter of replacing them with the supplied FAST sensors. They simply thread in, as they are all standardized threads.
This truck runs like a whole different animal. The lean pop under full-throttle upshifts is gone, and the tendency to run into the rev limiter during up shifts is gone, too. With FAST's Dual Monitor, Richard was able to watch the engine and monitor it every step of the way to make adjustments as needed. Power across the board has been increased, along with a healthy dose of torque. You may wonder why our peak numbers are so exciting to us-as they barely beat out our prior numbers. We'll recap for you. The truck was originally tested with a hand-held programmer set for 91-octane tuning. Our new tuning is for 87-octane fuel and we still made more power. Not just peak, but across the board. Our peak numbers were better by 3.07 hp and 9.6 lb-ft of torque, but that was well up the rpm scale where normal driving duties don't necessarily go. The big news is what's commonly referred to as the "area under the curve." Down at 3,000 rpm-where normal street shifting occurs during casual driving-our 4.8L was making 20 hp and 30 lb-ft of torque more than before. This is due to the HP Tuners software's ability to make incremental changes. We think those numbers are huge in comparison and our daily grind with that truck is much improved. We now have more power, better shifting, good gas mileage, and we're paying less at the pump for the pleasure. That's something to be excited about.
The supplied harness extensions have these safety-style plugs, which are similar to what are found on ECM harnesses. It was just a matter of running the cables away from heat and moving components; since the truck will be physically driving on the dyno machine. | 
Once the cables were routed to the interior of the Silverado, they were each plugged in to the FAST display unit. Each cable has a different plug, so right and left can't be confused. |
Moving on to the goods, we fashioned a 12-Volt plug for the auxiliary power port and turned the FAST unit on. It's overly simplified and the screen merely states "Read A/F" and "Advanced Options." | 
Pressing "Read A/F" took us to the warm-up screen where a cool flame flashes across the screen while waiting for the sensor elements to warm up and begin displaying. |
You can see that when idle, our Silverado is sitting at 15.2 to 1 A/F. A normal EFI idle should be between 13.0 to 1 and 15.0 to 1, so our reading said we were a tad bit lean. Richard Waitas and his trusty laptop will fix this small problem. | 
Viewing the Dynojet screen before our testing read 18.0 to 1 dead air, without the engine running, 72.5 degrees, 26.8-percent humidity, and 29.2 inches of mercury (barometric pressure). It was close to sea level SAE corrective settings. |