Ignition Coil Questions

[ellev8or]

92 PA
134,000 miles

I'm receiving a code 41 and was told by AutoZone that it could be four things; ignition coils, cam sensor, bad fuel economy and one other thing I can't remember.

Less than a week ago I changed the fuel filter, which stop the engine from sputtering when trying to accelerate. That cleared the sputtering but after clearing the codes I got another code 41. I removed the ignition coils and the ignition coil module and had AutoZone check them. The module was good after ten test runs but he checked the coils he stated that they were too weak and was not getting enough spark to the plugs. The readings for all four were in between 6.2-6.5. He checked four different new coils to show what the readings should be and their readings were 7.3-7.8.

My questions is, is there a prescribed reading for my specific vehicle? I'm wondering its reading low because of the iridium plugs I installed almost a year ago. Is the low range reading good for copper plugs and not for platinum or iridium plugs? I'm asking because since I've installed the coils I've just received another code 41. I guess the cam sensor is the last thing.

As always, you all are very helpful and I thank you in advance.

[MagicRat]

Not sure about the coils, but in my experience, these engines are notorious for the cam sensor failure.
Again, in my experience, its not the cam sensor that fails. The sensor detects the movement of a rotating magnet on the camshaft. It's the magnet itself that fails. Its either too weak or falls off - not sure. Or the cam sensor wiring circuit may be bad, as well.
So, probably you will still have the code if you change the sensor itself.



FWIW the sensor only comes into play when the engine is first cranking when you start the car. Its used to time the sequential fuel injection system so it actually is sequential. When the signal is missing, the engine uses a batch fire method, where (I think) 2 injectors fire at a time.
I drove around one of these cars for a long time in this condition. The idle was slightly rougher than normal, but it actually accelerated slightly faster. And theoretically, the mileage should be worse, but I never noticed a change.