Have an’02
Boxster S
. After driving about 30 minutes engine started running very rough and CEL came on. Got home and Durametric showed misfires on all cylinders. when I restarted the car the original faults still showed on the Durametric but the engine ran fine I.e. no CEL, no new faults on the Durametric. Took it for a ride and it ran fine. Any thoughts as to what may have happened.
Were you able to fix the problem?
My
987.1
CS with 64k miles has intermittent random misfires 10% of the time, always on start up, most the time the misfires occur after the car is not driven for a week or more, but it can also misfire after a day sitting idle. Sometimes the misfires are from cylinder 1 and 2, sometimes 5 and 6, sometimes all over. Sometimes It would start fine by restarting it a couple hours after the misfire. It seems to run perfectly fine once it's up to operating temperature.
My car has new
AOS
, new coils, new plugs, new low-temp thermostat, and new water pump from
pelican
.com. it does have a
borla
aftermarket
exhaust
, but that didn't cause any problem for several years after it was installed.
The intermittent part of the problem makes it harder to track down the root cause. This forum shows that many also experienced this problem of intermittent misfires, some had this problem with only 700 miles on the odometer. I'm wondering if this is part of the "charms" for those earlier generations of Porsches.
In the meantime, I'm going to continue with the "parts cannon" strategy.
Next
on the list will be
techron
(to clear the injectors) and liquid Molly (for stuck lifters)
Following along on the parts cannon approach, get a genuine accessory drive belt from the dealer (now only an $18 parts as our 987's have reached classic status
. Apparently some aftermarket brands of been causing false knock retard.
Have you had the sump plate off to look for plastic chain tensioner pieces? plastic in the oil filter?
Cheers,
Julian
I did see dark red plastic bits from the chain tensioner in the oil filter from two oil changes ago. Those bits were just a few and very small (pinhead size). It looks like those bits were a result of a couple of bad misfires from a couple of badly cracked coils. I didn't see any of those plastic bits in the last oil change. Given that the more of those bits are very few and very small, I think the chain tensioner is still in good shape.
I also replaced the accessories belt last year with a Continental belt. It's another instance of me lobbing parts at the problem
This. Happened to me on my 981. Porsche belt cured it.
