Playbooks

Beginner · short stepsExpert · spec · code · mm

Pick the situation. Read the left column. Say that at the window.

Twelve owner scenarios. Beginner script + genius measurements. SaferCar patterns — not a pirated TSB book.

WhoAudience: Owners in a named jam — brakes, noise, a light, a quote.Anyone who wants both altitudes on one card.
ClickControl: A playbook card. Then the beginner script.Playbook → steps. TSB desk and counter card live next door.
SayCounter: The left-column sentence. Then ask for the number on the right.Measurement first. Campaign lookup second. Parts last.

Playbooks · P0300 · Daily owner

Not a coil four-pack

Misfire is a pattern

P0300 is random misfire. P0301–P0308 name a hole. Coils, plugs, a vacuum leak, or low fuel pressure are the short list — not a tune-up package from the code title.

The light is flashing or it ran rough. A parts counter already has four coils in a basket. You need misfire counts and freeze-frame first.

Beginner steps

What you do

0 / 4 beginner steps

01Flashing light means stop loading the catA flashing CEL is catalyst-killing misfire. Reduce load. Do not highway-it to the shop “to burn it off.”Say: The light was flashing. I want misfire counts and a leak-down or plug look before a converter quote.
02Ask for misfire counts per cylinderMode 6 / freeze-frame / scan-tool counters. One hole is a coil, plug, injector, or compression story. All holes is fuel, vacuum, or a crank sensor.Say: Which cylinders are counting? I will not buy a four-pack from P0300 alone.
03Plugs before coils if they are dueIridium plugs are often do-not-regap. A 100k plug that is worn will take a new coil with it. One hole first.Say: Pull the plug on the counting cylinder before you sell four coils.
04Read fuel trims and ECT on the freeze-frameA lean trim plus misfire is a leak or a fuel-pressure story. A hot ECT vs a cold driveway code changes the ticket.Say: Print freeze-frame: RPM, load, mph, ECT, STFT, LTFT. I want that paper.

Do not

Do not throw a tune-up package from the code title.
Do not highway a flashing CEL.
Do not clear codes until you have the photo.

Expert notes

What the number means

P0300
Random/multiple. It is a pattern, not a SKU. Coil-on-plug Fords have a public pattern — still confirm the hole that is counting.
P0420 after a misfire
A melted brick can follow a week of flashing misfire. Fix the fire first. A converter does not fix a dead coil.

Open a live desk

SaferCar buckets this card answers: engine · not CR

Related patterns

Common failures by symptom. SaferCar pointers — not pirated TSB PDFs.

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