Hey guys tried searching on the forum but no luck.. 

 

I'm not sure if it's a common problem but my wife has a standard fg xr6 2011 with about 205xxx on it.. Zf6. No mods whatsoever

 

Now for some reason when it's in park or neutral it idles at around 800-850rpm but in drive it idles between 500-550rpm and also I've realised More so when the engine sits overnight and if it's a really cold night.. When we start the car the engine will fire no problem but the revs will fluctuate for 2 or 4 seconds between say 600ish to 1000rpm.. Doesn't happen all the time, maybe once every week and a half 

 

The box hasn't been serviced but is on the books and I'm planning on cleaning out the throttle body out this weekend when I have some time. Spark plugs were changed and battery has been changed recently too, Is there anything else that could possibly be causing this issue 

 

Thanks in advance 

Just after the car has been started it fluctuates?

Yeah pretty much as soon as I start it.. After it Fluctuates for a few seconds and then it'll rev a little higher as all cars do when they're cold and once it's warms up a little it'll drop to 550rpm

Is it stalling or feel like stalling?

 

How long since a service?

 

Clean out the intake plastic and check for leaks? (that's about the limit of my skills)

No it's not stalling or atleast it doesn't feel like it's stalling as it doesn't drop that low when the cars at operating temp and just idling in gear. 500rpm is usually the lowest

 

Service Intervals are every 10k and I have about 3k or 4k to go but this issue has been ongoing for a while and I just couldn't find an answer on google for my exact problem

clean the throttle body and intake tract. Check the spark plugs and coils for signs of corrosion.

 

Otherwise it seems almost normal.

Any Products you would recommend or just use a rag and get in there?

just carby cleaner does a good job on the intake tract, plus a clean wipe of the surfaces afterwards with either a rag or paper towel.

What about the battery. how old is it?

The battery I just changed like 2 weeks ago cos it was finished. Changed it to a delkor hi performance or something along the lines of that and it's a 680cca 

 

Also can anybody confirm if I can change the thermostat without having to flush the cooling system or burping the air out? As I need to change that too.. 

 

Cos you know.. Wife's car and she never maintains sh*t