No spark on cyclinder 1 and 5

ANSWER : Hi there. Try using a pair of small needle nose pliers to pull off the rubber boots from the spark plugs. As you pull, twist the rubber boots to break them free. If you cannot get the rubber boots off, then try using some mineral oil on the boots to aid them off, then clean off the oil with soap and water with degreaser. If you need further assistance with removing the boots from the spark plugs, then seek out a professional, such as one from Your Mechanic, to help you.

ANSWER : PCM’s rarely fail excepting cases where there is a whole model year, or production run, where a known issue arose in the field (e.g., bad capacitors being one example in certain Toyotas but even that was a long time ago). If you have a distributorless ignition system, the individual coil packs for those cylinders have to be tested as well as a variety of sensors that are in the control circuit. If it is actively misfiring on 1 and 5 try not to run the engine too much until it is repaired, because you could damage the catalytic converter as unburned fuel will enter the converter.

ANSWER : I would first look at the cap and rotor to see if there are any type of wear spots on either of them. That would be my first thoughts. If those are looking good, I would next take a look at the plug wires, and check the resistance on them to be sure they are still within specs. Also be sure there is no corrosion in the connectors for the plug wire to the cap. If all of this is looking good, you will probably want to check the hall effect sensor, and be sure that there is no play in the distributor shaft. If a bearing/bushing goes bad on the distributor shaft, it can lead to all kinds of ignition issues. If this is something that you feel you could use a hand to identify and/or repair, contact a certified mechanic, like the mobile mechanics available at YourMechanic.com.

ANSWER : Hi there. What led you to the need to replace those mentioned parts? What were the diagnostic steps to determine the fault or faults? When a misfire code is stored, that means that the ECM detected a slow down on the combustion stroke of those cylinders specific to the codes stored. What caused the misfire? The ECM does not know why this occurred, only that it has detected the occurrence. There could be a whole host of causes from electrical to fuel to spark to a sensor to the ECM to an internal mechanical fault. The simple fact is that without a proper inspection using proper diagnostic tools and processes, the attempted repairs can become very expensive. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.

ANSWER : This is a tough one because the self-diagnostics on your car are not very sophisticated. The light is on because the ECU is not seeing what it expects at the O2 sensor. When the engine is fully warmed up, there should be a regular sweep from .1 to .9 volts from the O2 sensor about 2 times a second. Replacing the sensor was a good first step, but if there is something about the engine that keeps the mixture from sweeping in response to the sensor voltage, the light will come on. I would check for vacuum leaks first. Then check for any leaks in the exhaust upstream of the sensor. Checking for a ground is good, but be sure that is at the exhaust. Sometimes the exhaust can become electrically isolated from the rest of the car. Some exhausts have a ground strap to prevent this. If you decide you need help with this, contact Your Mechanic. They can send a technician to your home or office to check out your Honda and advise you as to what needs to be done.

ANSWER : Either a failing crankshaft sensor or impulse wheel could be the cause of the fluctuating RPM reading. The crankshaft sensor signal is often used to start both fuel pump operation and start the ignition coils with the camshaft sensor setting the sequential injection and ignition firing order.

You may want to have faults read out of the ECM prior to replacing the crankshaft sensor and look at the crankshaft sensor wheel. If the sensor is mounted on the front of the engine the sensor wheel may be part of the dampener and may have slipped or vibrates. If it is a sensor wheel that is part of the flywheel, a bent tooth may be the cause. To have this resolved, you may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the equipment and expertise to correct this hard starting issue.

ANSWER : Hi there:

It would be best for you to review these two links; the first describes what the P0151 OBD-II Trouble Code is and what typically causes it, and second, the P0131 code and what it means.

ANSWER : If you have a Check Engine Light on, first check for those codes to determine what engine management thinks is going on. If no trouble code, check the ignition fuse behind the driver side kick panel (carpeted panel at foot level on the left – for left-hand drive vehicles). If the engine is spinning quickly, and doesn’t appear to be meeting any resistance (as a motor with good compression would have), you may have a broken timing belt. If so – STOP, call a professional mechanic, like a certified technician from YourMechanic for help.