I let my car sit for a few weeks and now after I drive it a few miles it misfires when accelerating, it has code 16 fuel injector. After it cools it runs fine for a few miles again.
I just replaced the ignition coil with a autozone one along with wires, cap and rotor about 6 months ago because a similar problem. 02 is a denso about 2 years old.
A main fuel relay would make the car not start right? it starts fine. I hope it’s not the coil again 
i would start by pulling the spark plugs. you may be able to spot the problem cylinder by inspecting them in order. it’ll help further narrow down the issue
you can rule out ignition by using an HEI tester. cheap and easy to use tool. simulates load on the ignition system
After you have checked what welfare suggested inspect the fuel injector circuit. Youve thrown a code 16 and you have a misfire. Its most likely a fuel injector, fuel injector resistor, pressure regulator, pressure regulator cut-off solenoid valve or contaminated fuel.
Inspect the spark plugs to ensure they are getting fuel.
Reset the ecu. Start the engine. If code 16 does not return its possible its an intemittent failure. Or like you said youll have to test drive for it to come on. Check for loose connections at the fuel injectors, injector resistor and the c318 round connector on the drivers shock tower.
If the code returns check each fuel injector for clicking with a stethoscope during idle.
If you find one that does not click, disconnect the injector connector and measure the injectors resistance. Should be between 1.5-2.5ohms. If not replace the injector.
Now if youve measured 1.5-2.5ohms on the injector, turn the ignition on and measure battery voltage between the injector connector red/blk terminal & body ground.
No battery voltage is shown then turn the ignition off and disconnect the resistor. Turn the ignition back on and check for voltage between the yel/blk terminal and body ground. Replace the resistor if there is voltage or find the open red/blk wire. You can also test the resistor for continuity to ensure its faulty.
If there is no voltage however, there could be an open yel/blk wire between the resistor and the main relay.
absolutely i agree. measure injector coil resistance. my feeling is a shorted coil. still works, but under load, unable to saturate.
to diagnose a code it’s always best to understand the system and how it is monitoring. how does the ecm know there’s an injector issue? typically, an ecm will have what’s called voltage samplers. it’s a slight resistance in the circuit before the load. the ecm then monitors the voltage drop across that load and compares it to it’s value of max and min to determine rationality… typically, that is. this means that a shorted coil could definitely trip a code on a self check or continuous monitor. especially since the problem only seems to occur under load
just thought about this again, and it makes perfect sense. the monitoring system. because the ecm only sees the resistance variation on the load side, it cannot offer specific injector fault. only “injector fault”. since all injectors share the same power feed but are grounded individually through the drivers in the ecm. cool stuff