986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Continued performance issue (but may have found something)

geraintthomas · 04-27-2018, 06:40 AM

So to continue on with my previous problems, I originally thought I had a vacuum leak but lately I'm not so sure.

It's completely inconsistent. Some days the performance will be brilliant, others will be lacking in torque, and some days will have choppy acceleration and deceleration, as if it can't make up it's mind whether the throttle is being applied or not at light throttle inputs.

MAF has been changed, so has the AOS, and TPS seems accurate.

Now, I've just discovered this:

https://youtu.be/Mg_49U5vqdI

See the rev needle bob up and down? I've pinned the throttle at 2.75% and that's not moving, however the revs are fluctuating between 150rpm and 200rpm.

I've noticed this happening when reversing and pulling off, where the revs would move up and down slowly as if I was feathering the clutch or throttle. This is also the issue that caused my previous bogging when pulling away, as the revs would fluctuate too low when I applied throttle, causing the car to bog for a second.

I've checked the coil packs and they're cracked. One of my coil packs has this part missing completely (highlighted in yellow):

No rubber end at all - I pulled it out of the tube.

Now yesterday, I applied full throttle from about 10mph, and the car felt like I had jabbed the throttle, let go, then jabbed it again, like there was a sudden and instant loss in power.

I don't want to jump to conclusions here, but... could my problems all be to do with coil packs? And not a vacuum leak after all?

04-27-2018, 06:40 AM	#1
geraintthomas Registered User Join Date: Nov 2015 Location: South Wales, UK Posts: 852	Continued performance issue (but may have found something) So to continue on with my previous problems, I originally thought I had a vacuum leak but lately I'm not so sure. It's completely inconsistent. Some days the performance will be brilliant, others will be lacking in torque, and some days will have choppy acceleration and deceleration, as if it can't make up it's mind whether the throttle is being applied or not at light throttle inputs. MAF has been changed, so has the AOS, and TPS seems accurate. Now, I've just discovered this: https://youtu.be/Mg_49U5vqdI See the rev needle bob up and down? I've pinned the throttle at 2.75% and that's not moving, however the revs are fluctuating between 150rpm and 200rpm. I've noticed this happening when reversing and pulling off, where the revs would move up and down slowly as if I was feathering the clutch or throttle. This is also the issue that caused my previous bogging when pulling away, as the revs would fluctuate too low when I applied throttle, causing the car to bog for a second. I've checked the coil packs and they're cracked. One of my coil packs has this part missing completely (highlighted in yellow): No rubber end at all - I pulled it out of the tube. Now yesterday, I applied full throttle from about 10mph, and the car felt like I had jabbed the throttle, let go, then jabbed it again, like there was a sudden and instant loss in power. I don't want to jump to conclusions here, but... could my problems all be to do with coil packs? And not a vacuum leak after all? __________________ Porsche Boxster S Type 986 Bi-xenon Headlight Upgrade \| 987 S 18" Anthracite Alloys \| Android Head Unit \| 5000k 55w HID's \| 5000k Cree DRL's \| 5000k Cree number plate lights \| Cree LED Indicators \| One-touch roof operation \| Bypass exhaust pipes \| Parking sensors \| Ambient footwell lighting Last edited by geraintthomas; 04-27-2018 at 06:43 AM.