A typical ford engine code po301 code is set when there is a misfire in cylinder 1. Most “300” codes involve the firing of the cylinders. Each cylinder corresponds to different number at the end of the code indicating which cylinder is misfiring. For example, po301 indicates a misfire in cylinder 1, 302 = cylinder 2, 303 = cylinder 3 etc. Now this “only” indicates that the computer is “detecting” a misfire in cylinder one.
This could be from a bad spark plug, a bad spark plug wire, or a bad coil / distributor cap. Each of these needs to be checked to localize the problem. It could be something as simple as a loose plug wire or as severe as a coolant filled cylinder resulting from a blown head gasket. But more than likely, it simply means that it might be time for an inspection of the plugs and wires. I have found that most of the time, a simple “tune up” solves the problem as well as increases your gas mileage.
As a mechanic, this is a typical engine code that most every car comes across in its lifetime. (I say “most” due to new electric cars with no internal combustion engine). If you are handy with a socket wrench it’s an easy check. There are many different engines and you must first find which plug wire goes to Cylinder 1. You can locate cylinder one very easy these days by simply typing in your year, make, model and “firing order” into any internet search engine and click Images.
I have found this to be easy and quick. Now you know where cylinder one is. First look at the condition of the spark plug wires (why not check them all while you’re at it) and check for any rubbing marks or burnt places. Next inspect the connecting “ends” and make sure they are snug. If they appear to be ok then nine times out of ten they are, but don’t let appearances fool you. Remove the plug wire and inspect for damage or breaks. Remove the spark plug and inspect for a burnt tip, bent tip, white powder, or black soot. If it looks bad…most times it is and it’s not firing properly.
Also take a close look at the coil or (distributor on some older vehicles) at the other end of the wire, and check for any signs or burning. Any of these three items could be the culprit. In the shop, I will suggest a tune up, plugs and wires, fuel filter and top off the fluids. Reset the check engine light and see if the “mis” has stopped. This can be done by a handheld “scanner” plugged into the DLC under the dash and watching the misfire count. If the code comes back on, that tells me that the coil (which is next in line) is the culprit.
Coils can be expensive on some makes, so it’s cheaper to just do the tune up first (never hurts) and then if it needs a coil, just replace the one that’s bad. The ford engine code po301 is a common code and is relatively an easy fix.