Alan36 Posted June 2, 2023 Report Share Posted June 2, 2023 Car starts and runs fine burt at tickover the revs fluctuate a little bit, maybe less than 100rpm but it is noticeable. I cleaned the old maf when this issue was worse and it got to this point. I have now replaced that maf with a bosch part and it's still the same. The scanner doesn't highlight anything. Is it now likely to be coil packs? Quote Link to comment Share on other sites More sharing options...
Rav Posted June 2, 2023 Report Share Posted June 2, 2023 I had a similar issue and it was found to be an O2 sensor. Try that first. If you have an early car there are 2 at £100 each, or later cars have 4. 1 Quote Link to comment Share on other sites More sharing options...
Alan36 Posted June 2, 2023 Author Report Share Posted June 2, 2023 Would have thought that would have shown up on the scanner. Mine is a 2000, do you know if that has 2 or 4? Quote Link to comment Share on other sites More sharing options...
½cwt Posted June 2, 2023 Report Share Posted June 2, 2023 2 hours ago, Alan36 said: Would have thought that would have shown up on the scanner. Mine is a 2000, do you know if that has 2 or 4? 2 1 Quote Link to comment Share on other sites More sharing options...
bally4563 Posted June 4, 2023 Report Share Posted June 4, 2023 Vacuum leak …. Cracked oil filler tube, dodgy AOS , expose engine and spray around with WD40 when it’s running and see if it steadies out. 1 1 Quote Link to comment Share on other sites More sharing options...
iborguk Posted June 4, 2023 Report Share Posted June 4, 2023 6 minutes ago, bally4563 said: Vacuum leak …. Cracked oil filler tube, dodgy AOS , expose engine and spray around with WD40 when it’s running and see if it steadies out. Also check the oil cap is on right , i know of at least one member who fixed a similar issue with that cheap fix. 1 Quote Link to comment Share on other sites More sharing options...
fizz Posted June 7, 2023 Report Share Posted June 7, 2023 On 6/4/2023 at 8:50 AM, bally4563 said: Vacuum leak …. Cracked oil filler tube, dodgy AOS , expose engine and spray around with WD40 when it’s running and see if it steadies out. When you say spray around? You on about the serpentine belt area? The pulleys etc? Quote Link to comment Share on other sites More sharing options...
bally4563 Posted June 7, 2023 Report Share Posted June 7, 2023 No around any joints/pipes etc Quote Link to comment Share on other sites More sharing options...
zagamuffin Posted June 8, 2023 Report Share Posted June 8, 2023 Mafs porsche only I believe as supurios never work or so I’m told Quote Link to comment Share on other sites More sharing options...
½cwt Posted June 8, 2023 Report Share Posted June 8, 2023 6 hours ago, zagamuffin said: Mafs porsche only I believe as supurios never work or so I’m told Bosch is the OE part but if in a Bosch box rather than a Porsche box it is only about 60% of the price OE part. (Still £160 on Autodoc today}. Part no 986 606 125 01. When mine failed I got a 2nd hand one for £30, 3 years in it is still running fine so consider one from a breaker, you can buy 4 or 5 and still be in pocket but know they are OE parts. You do need an odd security bit to undo the retaining screws though. Quote Link to comment Share on other sites More sharing options...
Daboy3000 Posted June 8, 2023 Report Share Posted June 8, 2023 (edited) I have the same with my 2.5. This weekend I put fuel cleaner in it and it was running at about 1100rpm instead of fluctuating between 900-1000. Not sure what that shows. I have looked at my AOS and it's not pretty so I know that needs doing. I am pretty sure the plugs and coils could do with a change too. Edited June 8, 2023 by Daboy3000 Quote Link to comment Share on other sites More sharing options...
½cwt Posted June 8, 2023 Report Share Posted June 8, 2023 22 minutes ago, Daboy3000 said: I have the same with my 2.5. This weekend I put fuel cleaner in it and it was running at about 1100rpm instead of fluctuating between 900-1000. Not sure what that shows. I have looked at my AOS and it's not pretty so I know that needs doing. I am pretty sure the plugs and coils could do with a change too. If you think it is MAF then the 2.5 part number ends 124.00, not 125.01 as above 1 Quote Link to comment Share on other sites More sharing options...
Everywhen Posted June 8, 2023 Report Share Posted June 8, 2023 Could also be the Throttle body, I had fluctuating idle then it failed altogether. Quote Link to comment Share on other sites More sharing options...
BBB Posted June 8, 2023 Report Share Posted June 8, 2023 On 6/4/2023 at 8:50 AM, bally4563 said: Vacuum leak …. Cracked oil filler tube, dodgy AOS , expose engine and spray around with WD40 when it’s running and see if it steadies out. Cracked oil filler tube did this on mine. When I moved the tube it sheared completely. It's a pain to fit a new one as there is a join right under the engine cover, where it goes into the filler neck on the boot. Quote Link to comment Share on other sites More sharing options...
fizz Posted June 8, 2023 Report Share Posted June 8, 2023 3 hours ago, BBB said: Cracked oil filler tube did this on mine. When I moved the tube it sheared completely. It's a pain to fit a new one as there is a join right under the engine cover, where it goes into the filler neck on the boot. Ive got a cracked oil filler neck but i dont have a unstable idle.. dont think it can be that bad at the mo. I do need to get round to biting the bullet and handing it over to a garage to replace it. Quote Link to comment Share on other sites More sharing options...
Photogirl Posted September 8, 2023 Report Share Posted September 8, 2023 I had that for years and then developed a long standing and very elusive hot start problem. This was eventually diagnosed as a faulty purge valve solenoid. Replacing it (not expensive as I recall) also solved the bouncy needle. Quote Link to comment Share on other sites More sharing options...
Alan36 Posted September 10, 2023 Author Report Share Posted September 10, 2023 Can you tell me where that valve is? Quote Link to comment Share on other sites More sharing options...
Photogirl Posted September 10, 2023 Report Share Posted September 10, 2023 (edited) 15 minutes ago, Alan36 said: Can you tell me where that valve is? Top of the engine bay, by the manifold. Don't confuse it with a similar sounding thing in the front wheel arch. Part of diagnosing a faulty PVS is to get somebody to start the car while you stare at the exhaust - a very small, very brief, almost unnoticeable puff of black smoke is what you're looking for. You have to really look for it. A faulty PVS almost always causes hot start issues. Edited September 10, 2023 by Photogirl 1 Quote Link to comment Share on other sites More sharing options...
½cwt Posted September 11, 2023 Report Share Posted September 11, 2023 Marked in the parts picture below, 996 110 129 06 is described as 'vent line' and given it is £250+, I hope it is the line and valve, not just the line as the valve doesn't have a specific part number listed separately: 1 Quote Link to comment Share on other sites More sharing options...
pacificjuha Posted September 11, 2023 Report Share Posted September 11, 2023 This is the above discussed reasonable priced valve in that rather expensive plastic line: https://www.pelicanparts.com/More_Info/99611012906.htm?pn=996-110-129-06-M14&SVSVSI=784&DID=18538 The valve is very hard to try to fit in old hard plastic line, but can be done by using peace of for example same size coolant / fuel line with appropriate size adapter and jubilee clips etc. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.