Q: 08 trailblazer idles rough at light then hard vibrate when start to accelerate

The first thing to check for in any drivability problem is air leaks. Any air that gets into the engine without being measured will lean out the system and cause problems. Look at all the rubber hoses and boots under the hood to be sure they are well connected and in good condition. If the check engine light is not on, it probably should be. Turn the key on without starting the engine, the CEL should be on. This is a bulb check feature. If the light doesn’t come on with the key on, it is burned out or it has been removed. If the light stays on after starting it means there are trouble codes stored that can help in the diagnosis. These can be read by a technician with the appropriate scan tool. The burning rubber smell could be an oil leak, or it could be a slipping belt. You need to have somebody look at it who can tell you. Contact YourMechanic to have a technician come out to your home or office to check out your trailblazer and let you know what can be done for it.