2004 Chevy Blazer Fuel Injectors

I am brand new at this thread but I am finding them very informative for the diyer. The problem I am having is trying to figure out exactly what type of fuel injectors I have on my 04 Blazer 4x4. The haynes manual shows CMFI and CSEFI. Looking at the pictures, I believe I have the CSEFI. The GM service dept says I have the LU3 engine. The reason I am dealing with my fuel injectors is because one day after work, my service engine soon light came on. It ran like a 3 legged dog, but I managed to get it home to check the codes. The 1st code was P0200 which is injector circuit open, then it was followed by P303 which is cylinder 3 misfire. After much research, I have concluded that cylinder 3 injector is bad because I ohmed it out with my meter and it is reading over 19 ohms when the other 5 are reading between 11-12 ohms. My questions are .....
Can a clogged or partially blocked injector be giving me this high resistance reading and is it repairable with simple injector cleaning solvents? Or do I really need to get a new injector and disassemble the top half of the engine? Any answers would be greatly appreciated!

That is a hard one to call.
Cleaning will not help on injector circuit or restiance.
Injector restiance on room tempt is 11-14.

The code 200 is fuel injector control circuit.
Could be open circuit or voltage problem.

Always check the injector plug in.

And for injector pulse on that cylinder that has the miss.

Confirm good proper fuel pressure 60/66 lbs.

Is it a dead miss all of the time or just a ramdom miss?

MT,
thanks for the quick response. I would love to check for the injector pulse on each cylinder but I am very new to these fuel injectors circuit. Could you please explain how I could check for the pulse? Also how would I check the injector plug-in? The connector mounts on top of the upper intake plenum and it is suppose to connect to all 6 injectors at the same time. The only thing I can think of is to carefully check the female pins on the connector itself to make sure it is connecting to the injectors. It could very well be something this simple and I hope it is. I will check this connector over very thoroughly in the morning. Thanks for that tip.
This problem is a dead miss all of the time. I have tried numerous things to try and get it to stay cleared but it keeps coming back and soon as I restart it after clearing the codes. Always the same 2 codes.
I have confirmed good fuel pressure. It is staying right around 60psi when running and with key on engine off, it runs up to about 55psi.

Each injector has a 2 wire circuit.
One wire is 12 volt feed and other wire is a ground circuit that the VCM uses to trigger/pulse injector.

A injector noid light across the two wires should show a injector pulse.

The plugin sometimes does not make a good connection.

Make sure it is plugged down good an tight.

Aso check the wiring at plugin and terminals.

Take a drill bit thge same size as the injector prongs and use back side to check for a good fit at the plugin terminal.

Is the spark plug for that cylinder dry or wet on the end when it is missing?
Got good compression on all cylinders?

You need 60/66 lbs of fuel pressure.
It needs to be 64-65 lbs on engine cranking and or cold start.

Also cherck fuel prssure as outlined below.The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.