what does "multiple misfires" code usually indicate
The most common problem is the spark plugs, but you can also have coil trouble, or injectors with poor flow, there can be any number of things, but do the plugs first.
Also replace the fuel filter is it hasn't recently been replaced.
Search Chevrolet TrailBlazer Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet TrailBlazer Experts