i would:
check batt voltage while engine is running. If it is less than 13.5 i would check the charging system
Using mechanics stethescope, check and compare all 6 injector sounds (clicking). If any injector is not clicking test the circuit with a NOID light. If cyl 6 sounds different, perform injector leak test with fuel pressure gauge installed onto fuel rail and car off.
if injectors are ok I would disable the fuel pump and check strength of spark @ cyl 6. you can do this by pulling fuel pump relay/fuse, removing cyl 6 wire from engine, installing properly gapped spark plug into coil, and using a thick wire with aligator clips on either end, connect threads of plug to good engine ground. have amigo crank engine while inspecting quality of spark. blue is good, orange/red is weak. If spark is weak check coil circuit.
check spark plug for proper gap/part number. inspect plug for indicators of running rich or lean burning oil etc
perform compression test
using scan tool check for proper fuel trims and coolant temp readings.
check egr function
remove valve cover to check for broken valve springs
if all else fails try new ECM
good luck
check batt voltage while engine is running. If it is less than 13.5 i would check the charging system
Using mechanics stethescope, check and compare all 6 injector sounds (clicking). If any injector is not clicking test the circuit with a NOID light. If cyl 6 sounds different, perform injector leak test with fuel pressure gauge installed onto fuel rail and car off.
if injectors are ok I would disable the fuel pump and check strength of spark @ cyl 6. you can do this by pulling fuel pump relay/fuse, removing cyl 6 wire from engine, installing properly gapped spark plug into coil, and using a thick wire with aligator clips on either end, connect threads of plug to good engine ground. have amigo crank engine while inspecting quality of spark. blue is good, orange/red is weak. If spark is weak check coil circuit.
check spark plug for proper gap/part number. inspect plug for indicators of running rich or lean burning oil etc
perform compression test
using scan tool check for proper fuel trims and coolant temp readings.
check egr function
remove valve cover to check for broken valve springs
if all else fails try new ECM
good luck