Hows your 3.4 CS when cold? - Page 1 - Boxster/Cayman - PistonHeads UK

My flat six is lovely and smooth, but when stone cold the first couple of miles are a bit different (987.2 manual). I'm not sure of the technical term but the engine is just a little wobbly, a little hesitant almost but not misfiring. It’s nothing severe and nothing scary, but I suspect I would not be alone in noticing it. I only notice it in 1st or 2nd gear, mainly when accelerating round tight corners on my housing estate or accelerating away from speed bumps. I try and keep the revs above 1500rpm and closer to 2000rpm even in first, so the engine is not labouring. Also I plugged my OBD scanner in and found my idle varies between 640-700rpm (at running temperature), is this correct? I can feel a gentle pulse sometimes, but I know some sporty cars have this engineered in.

987 are renowned for the little stumbles when cold; if you start and immediately drive off then you'll notice a distinct bunny hop for the first 10 -20 seconds - most don't notice it but once you've picked up on it you can recreate the scenario fairly easily. Its normal by the way. During warm-up and for at least the first 120 seconds of running from cold start the engine is running with large valve lift and retarded ignition timing; this combined with running the auxiliary air pump helps to bring the Catalysts up to working temp in as fast a time as possible. During this 'warm-up' period the engine is running through the toughest conditions in regards to smoothness; some let the car run for two minutes (you'll hear and feel the system change to normal map quite distinctly) but generally you can drive through it.

Pope said: 987 are renowned for the little stumbles when cold; if you start and immediately drive off then you'll notice a distinct bunny hop for the first 10 -20 seconds - most don't notice it but once you've picked up on it you can recreate the scenario fairly easily. Its normal by the way. During warm-up and for at least the first 120 seconds of running from cold start the engine is running with large valve lift and retarded ignition timing; this combined with running the auxiliary air pump helps to bring the Catalysts up to working temp in as fast a time as possible. During this 'warm-up' period the engine is running through the toughest conditions in regards to smoothness; some let the car run for two minutes (you'll hear and feel the system change to normal map quite distinctly) but generally you can drive through it. Cheers Pope. Any idea on whats considered a normal idle? Edited by Beknown on Sunday 24th August 20:20

I get this on my 987 Cayman as well. The engine note also sounds a little different at first and I guess it's more noticeable with the engine actually being in the cabin.

Thanks Pope - used to think mine was a cracked coil pack or something. It's fine in the morning by the time I've jumped out to close and lock the garage door but leaving work, on little or no throttle to adhere to the 10mph speed limit on site (which is monitored) when I drive off immediately it's quite noticeable.

Are you driving off while it is still in fast idle? It lasts about 40 seconds and I guess may come back in if you drive off before the engine drops into normal idle (around 700rpm as you say). I find the delivery a bit lumpy for maybe 2 minutes and, as Pope says, I understand it to be normal. I think you're probably right to keep the revs up a little for the first few minutes. I like to keep mine at around 1800 or 2000 revs for the first 5 minutes or so and then run it between 1800 and 2500 for the next 5 mins and then 1500 to 3000 for the next 10 mins. I don't actually consciously think about the above - its just how I seem to drive it while the engine is cold. I think the engine is up to a reasonable operating temperature in about 12 mins of normal driving and properly good to go in 25 mins, but the may be b ks as I am just going by how it feels to me.

I've got this issue on my 3.4 981 as well. The car bunny hops on a constant throttle. It is particularly noticeable as my driveway runs up quite a steep incline. I think it is just the car running super rich for the first 10-20 seconds or so and then the fuelling / mapping is smooth. It just have to accelerate fairly briskly, then come off the gas towards the top of the incline to minimise the risk of bunny hops. It is mildly annoying. Almost Italian in fact!

SimonOcean said: I've got this issue on my 3.4 981 as well. The car bunny hops on a constant throttle. It is particularly noticeable as my driveway runs up quite a steep incline. I think it is just the car running super rich for the first 10-20 seconds or so and then the fuelling / mapping is smooth. It just have to accelerate fairly briskly, then come off the gas towards the top of the incline to minimise the risk of bunny hops. It is mildly annoying. Almost Italian in fact! Identical scenario here. I would say these are strange traits for a £60k car but I'm not really qualified to criticize the reasoning behind it.

I've never known my 987 to do this. It idles high for about 30 seconds but by the time I drive out of my garage, lock the door and get back in the car the revs have dropped to about 750. For the next minute or so I drive very slowly down the narrow lane at the back of our house so I think I'd have noticed if it was hopping on a constant throttle.

That's a bit of an idle variation. The idle should be rather steady. Could be the signs of an intake air leak. Check the oil filler tube cap when the engine is idling. Listen for any signs of air leaking. Yet another and more common source of an intake air leak is the AOS. These start to fail and in some failure modes develop an air leak at least at low engine speeds. Later of course other symptoms appear.