Coge reading P0300. 3 &6 Cylinder has no spark. Changed ignition coil. Stll 3 & 6 has no spark. What next>

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Move plug number 6 and move it to plug hole number 1, and 1 to 6. Does the misfire move?

Yes, the plug is faulty or incorrectly gapped.

No, do the same with a coil.

Cylinder 6 could have other issues, spark plug lead, compression, valves, injector.

A pro grade scan tool computer can diagnose all electrical issues.

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Ignition coil one and six or course.The 3.7L uses separate ignition coils for each cylinder. The one-piece coil bolts directly to the cylinder head. Rubber boots seal the secondary terminal ends of the coils to the top of all 6 spark plugs. A separate electrical connector is used for each coil.
Because of coil design, spark plug cables (secondary cables) and a distributor are not used.
Two knock sensors (one for each cylinder bank) are used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery voltage to each ignition coil.
The ignition system consists of:
² 6 Spark Plugs
² 6 Separate Ignition Coils
² 2 Knock Sensors
² Powertrain Control Module (PCM

p0171 is fuel injection system too lean - bank 1
possible causes
- Intake air leaks - Faulty front heated oxygen sensor - Ignition misfiring - Faulty fuel injectors - Exhaust gas leaks - Incorrect fuel pressure - Lack of fuel - Faulty Mass Air Flow (MAF) sensor - Incorrect Positive Crankcase Ventilation (PCV) hose connection
p0304 is cylinder 4 misfire detected.
possible causes
Faulty spark plug 4 - Clogged or faulty fuel injector 4 - Faulty ignition coil 4 - Fuel injector 4 harness is open or shorted - Fuel injector 4 circuit poor electrical connection - Ignition coil 4 harness is open or shorted - Ignition coil 4 circuit poor electrical connection - Insufficient cylinder 4 compression - Incorrect fuel pressure - Intake air leak
p0305 is same as above but cylinder 5.
p0306 is same as above but cylinder 6.
p0300 is random misfire detected
possible cause
Faulty spark plug (s) - Faulty ignition coil (s) - Clogged or faulty fuel injector (s) - Intake air leak - Fuel injectors harness is open or shorted - Fuel Injectors circuit poor electrical connection - Ignition coils harness is open or shorted - Ignition coils circuit poor electrical connection - Insufficient cylinders compression - Incorrect fuel pressure

bad for coil, have them test for continuity

Like Ronald Wilson said it could be something linked to the ignition ( ignition coil, spark plugs or spark plug leads ).
No injectors or oxygen sensor.

P0353 CHEVROLET Description The ignition system on the vehicle uses individual ignition coils for each cylinder. The Powertrain Control Module (PCM) controls each ignition coil operation. The PCM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder.

Possible Causes - Ignition Coil harness is open or shorted
- Ignition Coil circuit poor electrical connection
- Faulty Ignition Coil 3
- Faulty Powertrain Control Module (PCM)
Read more: http://engine-codes.com/p0353_chevrolet.html#ixzz21kWvhhBc

Plugs get changed at 70,000 miles
I would suggest that you use the OEM
Plugs,they are made by NGK and are special
on my 2004 LS,I don't know about yours.

Clean the MAF Sensor with the CRC Product
for that

Change the 2 front O2 Sensors at 100,000 miles

Check fuel pressure at the fuel rail on engine

The coil you replaced on #6 ,even though you
have a PO306 Code,doesn't mean that was the
bad one. It is a COP Coil or Ford thing, you will
learn as you get involved with them

In some cases, you buy 1 new coil and walk it
from one cylinder to the next.

On single coil codes, you may get lucky,on multiple
codes or a really bad coil you won't

Your not using any fancy test equipment and
unfortunately a lot of repair shops have it and
don't know how to use it,including dealers

V6 or V8 ?

Sometimes you can use digital multimeter to check for ignition mis-fire.
With engine idling, touch spark plug wires, where applicable, one at a time and note the reading. You don't take the spark plug wire loose and you don't penetrate the insulation, just touch it. Some of the readings I've seen around .6 or .7 volts, not even a full volt. If you find one or two that are bouncing off zero, then you backtrack those. It's an inductive reading or whatever you want to call it.
Hopefully the misfire code will tell you which cylinder, then you check fuel--spark--compression on that cylinder. If p0300 mis-fire code, multiple cylinder misfires and the system can't determine which cylinder.
You might have a vacuum leak?
The basic for a rough idle, you check for a leak of some kind, fuel--egr--vacuum.

P0300 Random Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
according to this fault codes first mark ignition coils
3 ---------------- 6
2 ---------------- 5
1 ---------------- 4
RB-------------LB
this right banks and left bank, please remove Ignition coils with lids and spark plugs from right bank and swap with left bank, if fault code change as
P 0304 Cylinder 4 Misfire Detected
P 0305 Cylinder 5 Misfire Detected
P 0306 Cylinder 6 Misfire Detected
You can Identify it's a faulty ignition system then next swap ignition lids from ignition coils be careful each coils have two lids one short and other long bit deference and when you remove and fix it to the car keep in mind correct order because each coil two different fire for two spark plugs don't mix up, if you mix it can create the fault code.if you detect any fault ignition coils or spark plugs or lids replace that and also whether god or bad recommend to replace spark plugs, find the right that's most important thing, if this way couldn't found the any ignition fault next step is check fuel presser, when the engine running fuel presser must be around 4.5 bar without engine running must be 4 to 6 bar if the fuel presser too low need to check two different things one is fuel pump other is fuel injectors, in this case you can swap injectors from right bank to left bank and find is the injectors leaking, if not leaking faulty fuel pump.is this information helped you? if yes please leave a comment,

If there is a misfire, the cylinder that it is misfiring in will be recorded as a code in the computer.

Have the car scanned to determine which cylinder is bad. Then, replace the coil pack going to that cylinder.

Ignition Coil Pack Removal & Installation 2V Engine To Remove:

1. Twist the spark plug wires off of the ignition coil towers. Mark the spark plug wire positions so they can be installed in their original positions.
2. Disconnect the electrical connector from the ignition coil. CAUTION
   When removing the spark plug wires, a slight twisting motion will break the seal and ease removal.
   
   
   
3. Remove the mounting screws and remove the ignition coil.

To Install:

1. Position the ignition coil pack on engine.
2. Install mounting screws and torque to 53 in-lbs. (6 Nm).
   
   
3. Connect ignition coil pack electrical connector.
4. Match previously marked spark plug wires to ignition coil and install.

4V Engine To Remove:

1. Remove the RH cowl grille
   
2. Remove the screws and the water shield
3. Mark spark plug wire positions
4. Disconnect the spark plug wires from the ignition coil CAUTION
   When removing the spark plug wires a slight twisting motion will break the seal and ease removal.
   
5. Disconnect the ignition coil electrical connector
   
   
6. Remove the mounting screws and remove the ignition coil

To Install:

1. Position ignition coil pack. Install mounting screws and torque to 56 in-lbs. (6Nm)
   
   
   
2. Connect ignition coil pack electrical connector
3. Match previously marked spark plug wires to ignition coil and install
4. Position water shield and install screws
5. Install RH cowl panel