Engine surging or misfiring up and down while you’re driving.
Uneven engine revs and misfiring can affect drivability, but can also cause error codes to appear in your OBD-II Diagnostics system.
These codes can cause you to fail your local vehicle inspection, or at the very least can result in that very annoying Check Engine Light coming on.
The good news is that in many cases an engine that is running poorly can be repaired for very little money.
- P0300 Random/Multiple Cylinder Misfire Detected
- P0301 Cylinder 1 Misfire Detected
- P0302 Cylinder 2 Misfire Detected
- P0303 Cylinder 3 Misfire Detected
- P0304 Cylinder 4 Misfire Detected
- P0305 Cylinder 5 Misfire Detected
- P0306 Cylinder 6 Misfire Detected
- P0307 Cylinder 7 Misfire Detected
- P0308 Cylinder 8 Misfire Detected
- P0309 Cylinder 9 Misfire Detected
- P0310 Cylinder 10 Misfire Detected
- P0311 Cylinder 11 Misfire Detected
- P0312 Cylinder 12 Misfire Detected
Performing maintenance tasks like replacing worn spark plugs, inspecting plug wires, or even replacing an old, partially clogged fuel filter can make a huge difference in how well your engine is running.
Having an engine that performs well can save you a bundle of money. Even one hour of diagnostic time at your local repair shop can put a large hole in your wallet.
The list of symptoms and possible causes below should help you get a better idea of what’s causing your engine to act up.
Here are Some of the Possible Engine Symptoms and Causes,
While you are moving the engine misfires or surges.
The engine seems to start fine and will normally accelerate fine.
As you are driving and maintaining a steady speed, the engine seems to “speed up” slightly or it seems to miss and buck.
Any of these could be possible causes:
- If you have a carburetor, the choke may not be set properly, or the choke may not be working correctly.
The fix: Check the choke plate and make sure it is opening completely.
- The engine may be running too hot.
The fix: Check and repair cooling system.
- The fuel pressure regulator may be operating at low pressure.
The fix: Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (Generally not a DIY job)
- Your ignition timing may be set incorrectly.
The fix: Adjust ignition timing.
- Ignition system problem causing a weak spark.
The fix: If your vehicle has them, check and replace distributor cap, rotor, ignition wires and spark plugs. You should most likely have the coil packs looked at.
- There may be a fault in the computerized engine control system-Check engine control systems with a scan tool. Test circuits and repair or replace components as required. (Generally not a DIY job)
- The fuel filter may be partially clogged. This is an easy fix!
The fix: Replace the fuel filter.
- Torque converter (automatic transmission only) may not be locking at the right time, or it may be slipping.
The fix: Check lock up circuit or replace torque converter. (Not a DIY job)
- There may be a vacuum leak.
The fix: Check and replace vacuum lines as required.
- Possible internal engine problems.
The fix: Check compression to determine engine condition.
- EGR valve could be stuck open.
The fix: Replace EGR valve.
- You may have loose or worn drive axles.
The fix: Check and replace CV/universal joints as required.
- The fuel injectors may be dirty.
The fix: Clean or replace fuel injectors.