Intermittent revs when cruising

[PB987]

When driving and cruising ... revs go up only very slightly but this happens every second or so continuous ...

 

Anyone got any ideas ...

 

Thanks Mike ...

[Loren]

Exact model and year of your car please?

Also - manual or Tiptronic?

[PB987]

Hi ...

Boxster 987-1

2005

tiptronic

Also last week new oil and filter ...

Mike...

Edited April 17, 2016 by PB987

[Loren]

You need to read the fault codes.

Could be ab air leak (something bumped during oil change).

The fault codes will point to the issue(s).

[Hilux2400]

Is the oil filler cap on properly?  Is the oil dip stick in firmly? A few simple things to check for a start. 

[PB987]

Listen don't know who you are with the last help ... but if you going to give help on this website and to gain respect ... you will not get it in that way ... so on this occasion ... your advice is not helpful ...

[JFP in PA]

Listen don't know who you are with the last help ... but if you going to give help on this website and to gain respect ... you will not get it in that way ... so on this occasion ... your advice is not helpful ...

 

Slow down a bit.  While seeming odd at first blush, the questions asked are valid as either one of the suggested things to check could cause the circumstances you are encountering due to low level vacuum leaks, which are known to cause surging problems; particularly as you have just had an oil change .

 

I would also agree with Loren, get the car scanned with a Porsche specific diagnostic tool (PIWIS or Durametric) for both active and pending codes.  I would also look closely at both the fuel trim values and readings from the MAF at the same time.

[PB987]

apologies my friend ... have been around cars all my life ... it just seemed a bit odd ... but hey ... before oil change it was still doing the same fault ... the fault is just like overdrive on a car but every second ... once again sorry for my haste ...

[JFP in PA]

apologies my friend ... have been around cars all my life ... it just seemed a bit odd ... but hey ... before oil change it was still doing the same fault ... the fault is just like overdrive on a car but every second ... once again sorry for my haste ...

 

Not a problem.  Sometimes the oddest sound suggestions are based in hard earned experience.

 

Get the car scanned, we need a bit more information before we can offer more sound suggestions.

[Hilux2400]

Listen don't know who you are with the last help ... but if you going to give help on this website and to gain respect ... you will not get it in that way ... so on this occasion ... your advice is not helpful ...

It's OK don't be concerned no offence taken, but as JFP said sometimes really simple things can cause problems.  I didn't know the car had the fault before the oil change as you didn't say, hence my assumption that the two were linked. Some people have never put oil in a car.  

[PB987]

Ok ... What I have done is plugged into the OBD11 port nothing comes up all clear ... Admittedly My reader is not a Porsche reader ... I have spoken to a local Porsche specialist (http://porsche-repair-service.co.uk) she tells me it could be a sensor on the gearbox ... Possibly...

[JFP in PA]

Ok ... What I have done is plugged into the OBD11 port nothing comes up all clear ... Admittedly My reader is not a Porsche reader ... I have spoken to a local Porsche specialist (http://porsche-repair-service.co.uk) she tells me it could be a sensor on the gearbox ... Possibly...

 

Not to take anything away from your OBD II scan tool, but there are systems on these cars that a "global" OBD II scanner simply cannot access or read.  If your lady Porsche specialist has the diagnostic tool, I would let her have a look at it and the sensor she is questioning.

 

Without reliable diagnostics data, we are simply guessing and throwing out ideas.

[PB987]

Ok was trying to bypass the specialist but it seems that some things we can't do ourselves as I am a hands on car guy ...

For instance if a diagnostic tool that could find the problem cost say £200 I would rather buy one myself and fix the problem. But these readers cost thousands ...

Well looks like I am going to see her with the car ... Will keep all informed as to the outcome so we know the fault for future Porsche Boxster owners ...

Once again sorry for the mix up ... Mike ...

[Loren]

Ok was trying to bypass the specialist but it seems that some things we can't do ourselves as I am a hands on car guy ...

For instance if a diagnostic tool that could find the problem cost say £200 I would rather buy one myself and fix the problem. But these readers cost thousands ...

Well looks like I am going to see her with the car ... Will keep all informed as to the outcome so we know the fault for future Porsche Boxster owners ...

Once again sorry for the mix up ... Mike ...

 

http://durametric.com/

 

About 287 USD.

It will do most common DIY tasks and some professional tasks.

You can read what it does (for your model car) and it's limitations on their website.

[African Grey]

Your problem is:

4-5 gear driving at 40-50mph rpm moves +/-200 the LED's don't change.

Your problem can be one of the following:

1. Vacuum tube from the throttle body.

2. Faulty torque convertor

3. Faulty valves box.

 

Start with #1, then 2 then 3.