Timing help needed

Ok here goes. I replaced the intake gaskets on my 98 tahoe and it was not that bad, but I made one big novice mistake. I marked the distributor shaft but didn't mark the rotor button! I pulled the number one plug and held my finger on it until it pushed it out of the hole, to verify TDC, then I pulled the distributor and replaced it as close to number 1 as I could get it. It fired right up, but it feels sluggish, like it is under a load. I know that the computer does the adjusting of the timing, but is there anything that I can do without having to take it to a dealer to get it fixed?

A scan tool is required to adjust the timing on your 98. Any shop with the right scan tool can set the timing for you.

//2000CAYukon