Toyota Repair: 97 Four runner 3.4 misfires on 2,4,6, vent hose, ground connections

Question
Working on 97 3.4l Four runner. Truck was towed in had misfire code on #2. Ran great tried spraying with water on ignition,pulled plugs inspected coils and boots. Couldn't get to act up, replaced plugs and the 3 wires for 1,3,5. Customer had said was popping and running bad. After replacing items for maintenance started truck and was now acting up bad only showing misfires on 2,4,6. Tried propane around intake areas, adding fuel via vent hose with propane, reinstalled oe parts, can't get miss to go away. By looking at wiring diagram can see no way that 2,4,6 are tied together, looks like injectors aren't paired had like 250 misfires on pass. side cylinders and 0 on drivers side. Very unfamiliar with these engines any insight? Thank you  

Answer
When it was towed in there was a misfire code for cylinder #2(PO302) is this correct? Was it the only code at that time?
But after being towed in it ran great and the misfire was not duplicated but the spark plugs and wires were replaced, please correct me if I'm not getting it right.
There are two things I can think of that may cause this problem, first make sure that the ground connections on the left side of the intake chamber near the DLC connector are tight.
Recheck the plug wire installation, the three coils on the right bank also fire the plugs on #2,4,6 on the left bank, the #1 coil fires#4, #2/5 and #3/6 let me know if that fixes the problem.