1. Misfire. Vehicle Speed: A Misfire can be felt at any speed, but is most noticeable at low RPM. A misfiring engine is one of the most common reasons your Colorado will shake when accelerating. A vehicle’s ignition system consists of spark plugs, coil packs, and maybe plug wires. If it is an older model, it’ll have a distributor and coil. Backwoodssob. Okay guys I am in need of some advice. I installed a 3" strut spacer lift, and a 2.5" block kit in the rear. I also had the alignment done the very next morning. Truck looks damn nice like this. However now when I am accelerating between 20-40 MPH and when I am slowing down at any speed I get a vibration thru the whole truck.