Diagram of spark plug

The P0302 code means that the cylinder 2 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 2. If the problem persist more tests needs to be done. PO307 is the same thing except number 7 cylinder. Possible symptoms - Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation

Possible causes
- Faulty spark plug 5
- Clogged or faulty fuel injector 5
- Faulty ignition coil 5
- Fuel injector 5 harness is open or shorted
- Fuel injector 5 circuit poor electrical connection
- Ignition coil 5 harness is open or shorted
- Ignition coil 5 circuit poor electrical connection
- Insufficient cylinder 5 compression
- Incorrect fuel pressure
- Intake air leak
What does this mean? What does this mean?
Tech notes
The P0305 code means that the cylinder 5 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 5. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"
What does this mean? What does this mean?
When is the code detected?
Engine Cylinder 5 is Misfiring.
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation
P0305 Jaguar Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

Read more:
P0305 Jaguar Cylinder 5 Misfire Detected

At 150000 miles the plugs start to fail under hard acceleration the higher compression blows out the spark before it ignites the fuel. Random cylinder misfire causes the check engine light to come on. change the plugs!

code p 0306 is misfire detected no 6 cylinder causes electrics
more likely a bad injector , injector wiring or dirty tip

A P0300 diagnostic code indicates a random or multiple misfire,most likely cylinder number#2 (302). check the ignition system , to confirm it,check spark plug in 2nd cylinder , is it black in color as compare to other cylinders .if the spark plug look oily , may be 2nd cylinder piston Rings problem.its just general idea

With a service engine light blinking...don't drive it.

When replacing the spark plugs, double check that the boots on the coils are installed correctly. Check these again, and make sure to either listen for or feel a little click which tells you it's properly seated on the top of the spark plug. This is a common thing, happens all the time to people with TB's and Envoys. I've even done this myself.

In case you didn't know, # 1 cylinder is up front near the fan, then it runs in order to #6 at the firewall. Possibility....(don't take this as doubting you), maybe the wrong coil was replaced and one or more coil boots weren't set properly? Some things to check anyway.

www.engine-light-help.com/generic-engine-check-light-codes.html

P0305 - Cylinder 5 Misfire Detected
P0306 - Cylinder 6 Misfire Detected

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, The Powertrain Control Module (PCM) or Electronic Control Module (ECM) can determine that a misfire is occurring.

When is the code detected?
- Engine Cylinder #5 and #6 is Misfiring.

Symptoms:
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation

Possible Causes:
- Improper spark plug at cylinder #5 and #6
- Insufficient compression at cylinder #5 and #6
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #5 and #6
- Fuel injector #5 and #6 may be faulty
- Intake air leak at cyli

Possible Solution:
- Perform Injector Service
- Replaced Spark Plug #5 and #6
- Replaced Injector #5 and #6
- Replaced Ignition Coil #5 and #6

Hope helps.

u have 2 bad coils

go back & sleep with the mechanic, that always works for my sister.