How do I determine which coil is bad without a "check engine" light?

I would check the wiring that goes to the ignition coil. That coil may be bad and would die when it got hot and restart when cold. Check for voltage at the wire connecting that coil. Other bad wiring could be at the ignition switch, so wiggle wires under the dashboard that go to the key/ignition parts.

Hi

When any vehicle engine light comes on it generates a code, that code is read by a diagnostic tool that reads identifies and displays the code(s), to indicate the problem the senors have detected.


Codes can be reset to recheck if the fault is genuine or not, but without the tool its difficult to determine the cause of the engine light appearing.


Read the manufacturers suggestions or call a garage for a diagnostic quote.


cheers

Check to see if the Check Engine Light illumunates when you first turn the the key on. if it does most likely you have a faulty ignitor in the distributor assembly. There is a voltage drop test that can be done to determine if the ignitor or coil assembly is bad. If the Check Engine Light does not illuminate check for a good ground at the thermostat housing. Ground 101 or the ECU is bad. More times then not the ignitor is faulty since honda had switched to the external coil assembly by 1992.

You need to have the systems computer scanned for trouble codes.

when the light flashes, it means that the computer has determined a condition is present and is severe enough to cause damage to the catalyst system. You are most definitely exhibiting a severe cylinder misfire. Without knowing what code is in the computer, one can only guess that it is either a po300, or p0301-306. Most likely culprits are bad ignition coil, severe vacuum leak (pcv tube collapse).

when the check engine light blinks this is a sign of misfires but your going to need a scanner to determine which cylinders misfired and clear fault memory i would then recommend swapping coils and plugs from cylinders that misfired with ones that didnt and see if misfires migrate to determine bad coils or plugs

Without the engine running there is no oil pressure the oil pump is driven by the engine. Therefore with the engine turned off and the key turned to the on position, there is no pressure to read. If the check engine light is on with the engine running, you can have it scanned to determine which system needs attention. Most larger parts stores will scan for free but you need to buy a chilton or haynes manual for code meanings, individual component tests, and repair instructions.. (manuals are usually under $30)

First check power to the coil. Pull the connector off and probe the connector terminal from the pink wire with a 12 volt test light. Connect the test light clip to a ground point/bolt on the engine. The test light should come on when the ignition switch is on. If not, suspect the ECM-1 fuse is bad or the ignition switch is bad.
If there is power to the coil, next test the coil. Run a jumper from the battery positive terminal to the pink terminal on the coil itself. Pull the coil wire off the distributor and place the wire close (within 1/4 inch) to a ground point on the engine. Then, briefly touch a jumper from the black/white coil terminal to engine ground. The coil should release a spark. If not, replace the coil.
If the coil is good, suspect the crankshaft position sensor is bad or loose. I'm assuming your engine light is off, but the sensor can fail without setting the engine light. If the engine light is on, see if you can get a scan to see if a crankshaft sensor trouble code is set.
Please let me know if you have any questions.

might be something as simple as changing the spark plug or related wire, could also be damadge to the valve train or piston and cylinder bore

On many nissan altimas I have found bad ignition coils. Usually one bad one will creat a problem. The slp gets gounded through the ignition coil. When the ignition coil is going bad it shorts out other systems. Go to autozone or use a method to retrieve check engine light. If i knew the code it would be helpful. When the car is running rough disconnect one ignition coil with car off. Restart car. If car runs worse that means that coil is good. repeat process. If you have one coil disconnected and the car runs the same that means that ignition coil is not sending spark to your spark plug therefore creating a misfire and making your car run rough. That check engine light is most like likely linked to your slp light. If you find a bad coil using this teqnique replace it, your car will run better. I would like to know your check engine codes and this will determine problem better. If you have a misfire code or a po1300 code that points towards a bad coil