Can't shake a P0301 code

2003 3.0 flex fuel with 211k. Got a P0301 code last year and found one of the heater hoses had leaked at the junction and the coolant ran down onto the coil pack. Replaced the coil pack and plugs, everything ok. Now P0301 has popped again (right at smog check time). Anyway this time I replaced the plugs and wires but the code still comes back. Also now truck shakes on start up and seems to run better when warm, although does seem to still miss. Also the cel blinks intermittently. Should I replace the coil pack again? Any other suggestions?
Thanks.

Blinking CEL means "engine damage may occur", this usually happens at the time of a misfiring cylinder, if you let off on the gas pedal it should stop flashing.

You will need to do a compression test
Remove all spark plugs first
Then test 1 cylinder at a time and write down results
170psi is expected with 3.0l

But compression tests are about average compression since battery condition and compression gauges vary, which is why you need to test all the cylinders.
If all your cylinders are 150-155psi that means all is well, weak battery or gauge is off, but all is well

Compression is black and white, no guess work, no intermittent compression issues.
Once tested you can move on or save yourself some money if you do have a low cylinder, so no wasting money on a non-fix, i.e. new coil spark plugs, wires or fuel injector

Many shops also offer electronic compression test, they do work, and it is quick.
Laptop hooks up to engine computer
It disables spark and fuel while engine is cranked by starter motor
The speed of the crank sensor pulses can tell the compression of each cylinder, approximately, but point of the test is to see if #1(P0301) is lower than the rest which electronic test can tell for sure.

Reason I mention compression test is because your 2003 3.0l is very close to the 2004-2006 Ranger 3.0l TSB about Recessed Exhaust valve seats

TSB here:
TSB 05-26-3

FORD: 2004-2006 Ranger

ISSUE
Some 2004-2006 Rangers 3.0L-2V "Vulcan"vehicles may exhibit:
- Malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P0300-P0306 and P0316
- Rough running at various RPM
- Rough idle
- Misfire

ACTION
This may be due to an engine exhaust valve seat recession causing a loss of compression. Refer to the following Service Procedure to diagnose exhaust valve seat recession.
SERVICE PROCEDURE
1. Perform a power balance rest to clarify if a cylinder is misfiring. Identify and keep record of any cylinder that has a concern.

2. Perform a manual compression test with the spark plugs removed to locate any cylinder that may have low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.

3. If no low compression is found per shop manual instructions, proceed with normal misfire diagnostics per the Powertrain Controls/Emissions Diagnosis (PC/ED) Manual for the appropriate model year.

4. If low compression is found and it is a cylinder that had a misfire on power balance, perform a leakdown test to determine the source of leakage that may be causing the low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.

5. If low compression is found in a cylinder that did not have a misfire detected then proceed with normal base engine diagnostics per the Workshop Manual, Engine System, General Information, 303-00.6.

If the exhaust valve is identified as the source, replace both cylinder heads with the newly released service cylinder heads. Refer to the appropriate Workshop Manual, Section 301-01A.

PART NUMBER / PART NAME
6U7Z-6049-A / Cylinder Head Assembly

Instead of typing everything I did, read my posts a few weeks ago, titled:
3.0 liter, #3 misfire

94RoadkillRanger said:

Instead of typing everything I did, read my posts a few weeks ago, titled:
3.0 liter, #3 misfire

Click to expand...

Yeah I knew this is coming. I have a Saturn with 277k with the same exact issue. So you just replaced the right head?

Thanks

Yes, just the right head. But it also requires new head bolts, head gasket, intake gaskets, and replaced thermostat just because. My exhaust gasket was still in good shape from two years ago.

I determined I have a bad head gasket on the #1 cylinder. I'll be removing the heads and replacing the gasket et al. I'll also take the heads to the shop to be checked/replaced. I found a good video online that shows the job but I have a few questions.
When I remove the rockers and push rods should I just replace them since I'm in there?
Should I expect to be doing any valve adjustment or will I just torque the rockers to spec?
Is there any other tips I should know before I get started?
Thanks in advance.

I did not replace the rods. Inspect everything for sure. The re-manufactured head that I bought from A.Z. had all the valves ready to go. I literally just bolted it in. Tip: beware of proper head gasket for rear wheel drive.

Tip: beware of proper head gasket for rear wheel drive.[/QUOTE]

What does that mean?

I got Fel-Pro HS 9902 PT-5 02-08 FORD 3.0L V6 OHV

Thanks

Sorry,
I was not clear. Make sure you do not get the front wheel drive head gasket for the Vulcan engine.

OK Got it thanks.