Originally Posted by yellow69z28rs
I had EXACTLY the same experience.
Then I added headers, cat delete, and crank pulley, then the butt dyno picked up the 60 hp and tq gain!
Noticed after I've added some miles after the mod .. its pulling now. I think what happened was the ecu took some time to re map it self trimming the fuel and extra air that it is getting. It took me by surprise today.. i had it on 2nd gear from start sitting at a light. when i took off the back tires broke loose. I put down some serious smoke. If i hadn't let up on the gas i think it would have continued leaving a trail of white smoke all the way across the intersection.