Two problems related to engine stall have been reported for the 2004 Chevrolet Trailblazer. The most recently reported issues are listed below.
Car felt "stuck" in gear, wouldn't accelerate, low on transmission fluid. Added more fluid, replaced speed sensor, camshaft & crankshaft sensors. Still having issues with rpms going high, car slamming from one gear into another. Also cannot run heat while driving, fan draws power & causes engine to stall out. Car also burning through gas very quickly.
Engine stalled in traffic and idles rough on startup. Dealer reprogrammed idle control module. Engine surges and shakes under a load from power steering or alterantor. Dealer cleaned throttle body (only 4800 miles) and found large leak at evap vapor pipe. Continued to have problem. Dealership contact gm for help. Gm replied that "4. 2 liter motors have an inherent vibration at that speed. " gm technical assistance also stated "engine surge under is normal under load by design. " car is ticking time bomb for another stall in traffic and daily endangers my family.