987 Misfire - Started out of nowhere, left out of nowhere...
Discussion
Morning PH,
So yesterday I took my 2007 Cayman 2.7 (50,000 miles, recently serviced) out for a drive, after it's been sat in the cold for 2 weeks during the bad weather period. All was going well, until after 5 minutes the engine started to misfire, I first noticed this when I was in 5th at around 1600RPM, and I gave it any throttle the engine was juddering and jerking, if I dropped a gear the juddering seemed to disappear (anywhere above 2000RPM) but power was down. I drove along for a few miles thinking she might 'walk it off' but then the CEL came on 'Engine, visit workshop'. I stopped the car, thinking a reset might do her good now that she was warm... no luck. CEL still on and my heart was really sinking at this point!
I decided to carry on with my 30 mile journey (not sure if that was a bad decision), and just sit a little higher up in the rev range to prevent the juddering. The CEL was coming and going - it's wasn't on continually. Once I got onto a long section of A road, I was just sat at 50mph in 5th for 20 minutes or so, and the issue appears to have completely gone. I could accelerate from low down in the rev range without judder, no CEL, engine seemed to be fine. Later in the afternoon I drove home and all fine again.
However, I feel as if the power is very slightly down on before, and the sound is a little muted (but I think this could well just be paranoia!). What do you guys think happened? I'm a little mystified how the issue just came and went? Has it shut off one of the misfiring cylinders possibly - can the ECU even do that? Should I get on and change out the spark plugs (don't think they've been done yet) and coil packs? I also have an OBD scanner, should I connect it to my phone for some information?
Appreciate your time.
Tom
So yesterday I took my 2007 Cayman 2.7 (50,000 miles, recently serviced) out for a drive, after it's been sat in the cold for 2 weeks during the bad weather period. All was going well, until after 5 minutes the engine started to misfire, I first noticed this when I was in 5th at around 1600RPM, and I gave it any throttle the engine was juddering and jerking, if I dropped a gear the juddering seemed to disappear (anywhere above 2000RPM) but power was down. I drove along for a few miles thinking she might 'walk it off' but then the CEL came on 'Engine, visit workshop'. I stopped the car, thinking a reset might do her good now that she was warm... no luck. CEL still on and my heart was really sinking at this point!
I decided to carry on with my 30 mile journey (not sure if that was a bad decision), and just sit a little higher up in the rev range to prevent the juddering. The CEL was coming and going - it's wasn't on continually. Once I got onto a long section of A road, I was just sat at 50mph in 5th for 20 minutes or so, and the issue appears to have completely gone. I could accelerate from low down in the rev range without judder, no CEL, engine seemed to be fine. Later in the afternoon I drove home and all fine again.
However, I feel as if the power is very slightly down on before, and the sound is a little muted (but I think this could well just be paranoia!). What do you guys think happened? I'm a little mystified how the issue just came and went? Has it shut off one of the misfiring cylinders possibly - can the ECU even do that? Should I get on and change out the spark plugs (don't think they've been done yet) and coil packs? I also have an OBD scanner, should I connect it to my phone for some information?
Appreciate your time.
Tom
Edited by bomster on Monday 12th March 10:42
Edited by bomster on Monday 12th March 10:46
Edited by bomster on Monday 12th March 10:47
Following from the above, I got myself an OBD adaptor, and ran Torque.
It presented the following as 'Pending Faults':
P0303 - Misfire Cylinder 3
P0300 - Misfire Detected
I am taking from this, that the coil pack on #3 had some water ingress during the time it was sat stationary, and after driving for 30 mins or so the moisture evaporated and all is well?
Would this show that the coil packs are on their way out, and would be prudent to change? Or should I forget about it worry about it at a later date?
It presented the following as 'Pending Faults':
P0303 - Misfire Cylinder 3
P0300 - Misfire Detected
I am taking from this, that the coil pack on #3 had some water ingress during the time it was sat stationary, and after driving for 30 mins or so the moisture evaporated and all is well?
Would this show that the coil packs are on their way out, and would be prudent to change? Or should I forget about it worry about it at a later date?
My new (to me) 986 has developed a misfire after being sat outside during the bad weather. My garage isn't yet finished so it's resigned to sitting under a cover outside for a few weeks.
It ran fine on the test drive, but after starting it the other day it misfired badly at idle and with light throttle. A bigger "blip" and it sounded fine higher up the revs, but then settled into a horrible idle. Once warm it seemed to get better.
I have the same theory as you - corroded/cracked coil somewhere. Lots of moisture in the air over the last few days. And probably after a good drive it will be ok.
ECP are doing a set of coils for ~£100 with a discount code. Got new discs/pads to fit on the rear, so planning to fit new coils/plugs at the same time.
It ran fine on the test drive, but after starting it the other day it misfired badly at idle and with light throttle. A bigger "blip" and it sounded fine higher up the revs, but then settled into a horrible idle. Once warm it seemed to get better.
I have the same theory as you - corroded/cracked coil somewhere. Lots of moisture in the air over the last few days. And probably after a good drive it will be ok.
ECP are doing a set of coils for ~£100 with a discount code. Got new discs/pads to fit on the rear, so planning to fit new coils/plugs at the same time.
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