recently while sitting in traffic, my 1999 XKR (108k) has started to occasionally flash the RP msg - then the msg goes goes away - but when i pull away it has none of it's usual va va voom (like it's stuck in 3rd gear with no Supercharger) - when i turn the ignition off and on again -it's back to it's usual fabulous self straight away...
any clues?
Thanks in advance guys.

 

RP is often due to a lean condition and, given that you're seeing it mostly at idle, a vacuum leak is for sure a suspect.


A scanner that can monitor fuel trims in real time would be very helpful here. If fuel trim corrections are fairly large in the "lean" direction, and the short-term trim is highest at idle, and common to both cylinder banks, ... vacuum leak is a strong possibility.

 

Hi Thanks Dennis - would that explain the subsequent lack of power - then when i switch the car off and on again - all is well? The RP msg only comes on say twice in an 8 mile trip with a lot of sitting idling (terrible London traffic as per usual) when it comes on ( as i said) the car seem to lose a lot of 'zip' - soon and i turn it off and on again - all is well - the RP msg does not stay on - it goes away...

 

Not sure. But we know you're getting Restricted Performance lights, followed by periods of poor performance. I would track down the reason for RP lights, and see if fixing that will clear everything up.


My vote is to look at fuel trims for starters.


Good luck.

 

While you don't have you car listed in your signature I'm guessing it's a XKR. Dennis has good advice and you should follow through. My comments would be you mention sitting in traffic you are heating up, check your fluid level AND the SC iC Pump and ensure it's running (you can hear it spin when key is on, engine not running) it's located just below the air box.

 

Hi - i believe you guys are def on the right track, i have read that a guy changed his sc ic pump but changed the aux cooling pump 1st? he said the aux cooling pump doesn't 'throw out a code - just no heat??' after all that he checked his fuse and it was the fuse that was blown - where exactly is that fuse - i'll check that 1st - also someone said that when you get a RP msg it disables the s/c - explaining the lack or normal amazing power..
Thanks for taking the time guys - just to be clear again - it's a 1999 XKR Coupe.