Bog down/hesitation after changing gear

[PaulMc]

Hi Everyone,

2002 Base with 96K.

I have an issue that I hadn't noticed before, so assume is new, related to changing gear. Mostly, but not always, after changing gear and releasing the clutch, I get a "flat spot," or what feels like a bog down or hesitation as I put my foot down. I have experimented with shift points and whether I shift at 3K, 4K or even 6K rpm it seems to happen. However, running the car up through the rev range, say change up from 3rd to 4th at 3K and the running to redline, the car doesn't miss a beat.

The clutch has about 5K on it and the motor mount was changed recently (1K ago or so) The motor mount made a huge improvement in handling and shifting and I have also had the gearbox oil drained and refilled in the Spring (Porsche OEM fluid). This problem has occurred recently. One thing I did notice was if I ran the car hard for a few days consecutively, I thought it went away, but the car is still doing it.

This could be cockpit error, so I have tried getting off the clutch earlier or later, more gas, or less gas and it seems to be the same.

Any ideas on this would be appreciated! I also have a very small oil leak which is coming off the filter canister. I am pretty sure it is not related, but I can't see where it is originating from either....

Thanks everyone.

Paul.

[The Radium King]

there is a switch on the clutch pedal - when clutch is depressed the switch triggers a timing cut to drop power to facilitate gear change. perhaps the swtich is sticking intermittently?

[PaulMc]

Thanks! That must be it. I will get a new switch ordered. I didn't realise the clutch switch did that, I thought it was just for starting.

Many thanks for the quick informative reply.

Cheers,

Paul.

[The Radium King]

i think also for cruise control - cruise disengages on clutch depression, yes? do you have cruise, and does it randomly drop out on you? perhaps initially just check the plug at the switch and hit it with some contact cleaner.

[PaulMc]

I do have cruise, but it seems to work perfectly. I had read one post somewhere where someone had an issue similar to this, but not much else around the switch and its effect on the engine.

Is it the cruise switch that could be causing this rather than the interlock switch? The symptom fits the cause that you describe perfectly. After changing gear the power is held off for longer than it should be due to a "sticky," switch.

I might give the contact cleaner a shot, but by the time I have folded myself into the footwell, it might be more prudent to change out both switches.....

Cheers,

Paul.

[BoxsterInTheSun]

Originally Posted by The Radium King

i think also for cruise control - cruise disengages on clutch depression, yes? do you have cruise, and does it randomly drop out on you? perhaps initially just check the plug at the switch and hit it with some contact cleaner.

I have this exact same issue with my 2002 base model 986, it bogs down slightly after changing gear and starting to accelerate. I'm wondering if it's the switch that you're talking about in this thread?



There seem to be 2. I already ziptied the white one closed. Can I test the red one circled in yellow in the picture by taping the plunger closed? Or by removing it so the plunger doesn't make contact with the clutch pedal? The plunger on that switch is definatley "sticky" and doesn't go up and down freely.

Could this be my issue?

[PaulMc]

Follow-up to this.

I did remove the switch, disassembled it and cleaned. After re-install I didn't notice any improvement and in fact, the cruise control behaved oddly! On depressing the clutch the revs climbed instead of dropping.....During this period of low-cost repair, I had another switch on order from Pelican. It finally arrived last night and I installed it. I haven't had a chance to drive the car much, but the hesitation seems to have gone and if I am in cruise when I depress the clutch, the revs behave normally.

As an extra note, I checked with my durametric and found a "clutch switch position implausible," error. I reset this as part of the install of the new switch, so it is possible that my switch cleaning was ok and the fault code was still causing the problem, but for a few bucks the new switch is a better bet. For anyone that comes up against this, it is the red/black switch on the clutch not the interlock switch that I replaced.

Thanks for the help!

Paul.

[BoxsterInTheSun]

I'm not sure which switch was the issue, but what I outlined above has completed solved the problem I was having. Absolutely amazing that such a simple fix could solve what felt like such a big issue. Wish I had tried this before I pulled the throttle body and MAF sensor and cleaned them within an inch of their lives.

Thanks to the OP for pointing me in this direction, would never have guessed this.