Misfires + Rough Idle

[Hamstuh]

Hello All,

I have a 99 Boxster 2.5L runnin 0w 40 Mobil1 that recently started giving me some trouble.
Has about 187k miles, aside from just recently. its ran like a dream and never had any issues prior

Got a check engine light with codes:

STORED:
P0300 - Random/Multiple Misfires detected
P0306 - Misfire Cyl 6
P0304 - Misfire Cyl 4
P0305 - Misfire Cyl 5

PENDING:
P1319 - Misfire Emission Related
P1318 - Misfire Cyl 6 Emission
P1316 - Misfire Cyl 4 Emission
P1317 - Misfire Cyl 5 Emission

P1524 - Camshaft Adjustment Bank 2

Cars been taken care of and maintained since Ive owned it. The Misfires for 4,5,6 came first initially with noticeable fluctuations in RPM below 1500 RPM. Decided to do all plugs, coils, and plug tubes first to see if that would fix it. Codes came back some time later and i noticed a consistent small drop and raise of RPM just below 1000. Before this, ive already changed the MAF and O2 sensors just for ensuring other basic maintenance things were up to date. This all came out of nowhere so i doubt its anything critical. Ive test driven the car a bit and it runs amazing aside from those idle misfires at a light or stop sign.

Im thinking it could be AOS related ? or idle actuator related. Not sure as the Misfires have only come from 4,5,6 and never 1,2,3. Any assistance or recommendations would be much appreciated

[blue62]

P1524 is telling you that there is an issue with the cam shaft adjuster on bank 2.
It has an effect on cam shaft timing. It is most likely why your having miss-fires on all cylinders on that bank. You need to fix the P1524 issue first.

[Hamstuh]

Originally Posted by blue62

P1524 is telling you that there is an issue with the cam shaft adjuster on bank 2.
It has an effect on cam shaft timing. It is most likely why your having miss-fires on all cylinders on that bank. You need to fix the P1524 issue first.

looked a good bit into it online, just wondering what you would recommend a starting point would be for a diag on this case. does this automatically mean the adjuster is bad and i'd need to swap said ~$800 part out or something to be cleaned and potentially fixed

[pilot4fn]

Could be that adjusters chain guides (betweekn the cams) are worn out very badly and the adjuster does no more do it's job well.
If chain guiders on the adjuster have never been changed, those are already in need for that. Chain guides are very cheap, but best to change engine out (jes, some have changed those engine in...).

[blue62]

Originally Posted by Hamstuh

looked a good bit into it online, just wondering what you would recommend a starting point would be for a diag on this case. does this automatically mean the adjuster is bad and i'd need to swap said ~$800 part out or something to be cleaned and potentially fixed

The starting point is to determine if the adjuster functions or not.
It is an electrical devise so the electrical circuit portion can be tested with a volt meter.
It can be made to "test" actuate with the proper type of OBDII reader such as a Durametric or some of the Foxwell brand readers.

The second thing to consider is the high mileage ...there is very possibly high wear issues.
Access to things like the cams is very limited unless you pull the engine.
With these type of engine designs repairs can get costly.