Hey guys

I have an 04 mcs, about 60,000 miles. I've been battling an issue for a while and need some help. At idle, my rpms are jumping up high, up to 2,000 rpms. It doesn't happen all the time, it's random. Having said that, I don't think it's a vacuum leak because it's not constant. Nonetheless, I checked for a leak and can't find one. I swapped out the throttlebody, still same issue. I'm beginning to think it might be electrical? When it idles high, I can turn on my heat and it levels out. Ill meter the voltage and see of my battery is ok, but it's kind of a guess at this point. Does anyone have any ideas what could cause an unexpected high idle? Thanks in advance. I've got to pass emissions by the end of this month, so any input would be much appreciate. Thanks.

 

R53 high idle

 

Update. I checked my batterry. It's reading a healthy 14.1 volts when running, but it drops from 12.2 down to 11.9 on about a minute after shutting off the car. I think anything lower than 12.4 is bad so I'll replace the batterry and see of it helps the idle. It's the original batterry lol.

 

hey, Im new to this forum or any car forum for that matter. Di you find out what your issue was?
Today, while at a stop light, my '09 MCSc started going from 1-2000 rpms, over and over. it did this at multiple stops and Im just curious as to what it could be.
I dont have a warranty anymore, so hopefully not a huge deal.