986 CEL on after storage

[Stl-986]

Also, check for oil leaks around the spark plug tubes on the cam cover. This is typical of dry/cracked spark plug tubes. Ok to replace, cheap but just time consuming. These can cause misfires also.

for coils unless the crack is very obvious it will be hard to see them usually. cracked coils typicall cause misfires when driving in rain or getting them wet.

If you dont know when either were last replaced, it may be best to just replace all the plugs & coils, it isn't expensive.

[Rundtinden]

Both plugs and coil packs are fairly new. I could understand if one failed, but not all three on one bank simultaneously. There has to be another problem causing this. Read about a possible solenoid issue known to cause misfire codes on bank 1. Any information on this subject?

[blue62]

Originally Posted by Rundtinden

Both plugs and coil packs are fairly new. I could understand if one failed, but not all three on one bank simultaneously. There has to be another problem causing this. Read about a possible solenoid issue known to cause misfire codes on bank 1. Any information on this subject?

I some what agree with your line of thinking.
BUT
The car sat for two years
So the best thing to do is go with automotive tried and true diagnostic procedures.
That means simplest things first then work your way up step by step.
The plugs, coils, and any oil that could cause issues is the easiest first step.
If there is no issues with them then there's no cost.
Go to the next step.
Next would be the wiring harness to the coils.
Rodents like to chew the coating on wires for some damn reason.
You can test that out with a common Digital Multi Meter.
If these prove out all good then it's time to look for other causes.

Sticking to the basics helps prevent chasing your tail

Let us know how you go.

If the above does not fix the issue perhaps we can help you find the issue.

[Rundtinden]

Will change the plugs and check the coils
Cleared the faults and took it for a test drive today. It drives well. No hesitation on acceleration and no smoke or misfire. Drove approximately 60 km. I then decided to check the brakes and floored the pedal. The brakes are very good. But the cel came on again immediately! Coincidence? Turned around and drove 60 eventless km back again.
Hooked it up again and the same codes were present: P 300, 301, 302 and 303.
It was stored for two years with little fuel in the tank. Any possible problem here that will affect bank 1 cylinders only?

[blue62]

Originally Posted by Rundtinden

Will change the plugs and check the coils
Cleared the faults and took it for a test drive today. It drives well. No hesitation on acceleration and no smoke or misfire. Drove approximately 60 km. I then decided to check the brakes and floored the pedal. The brakes are very good. But the cel came on again immediately! Coincidence? Turned around and drove 60 eventless km back again.
Hooked it up again and the same codes were present: P 300, 301, 302 and 303.
It was stored for two years with little fuel in the tank. Any possible problem here that will affect bank 1 cylinders only?

Does your scanner show freeze frame data?
That is data showing the conditions or some of the conditions when the codes were set.
If I remember correctly most all OBDII scanners that show freeze frame data show data for the last code only.
But Since all your codes are related there may be a clue to whats triggering them in the freeze frame data.

Still need to look at the coils, plugs and wiring harness though.