I've had this car for about 5 month and it has about 250000ks on it, but drives perfectly fine, expect for one problem ive had since i got it. this is the second 850 ive had the last had various problems, but not this problem, it also had about 100000 more ks on it too.
Anyway i will try to explain the problem best i can. Sometimes when started it doesnt want to just idle, instead it will go through a cycle of hitting up through 1500 then dropping down below 1000 then back up until it conks out, but will eventually go back to running normal after a few more starts.
Also sometimes if ive been driving around and have to come up to a traffic light or travel slow from traffic my car wont want to come to a idle when stopped instead the same symptons said above and with the cycle the car with try to jump forward, i stop it moving with the breaks and it will fall back into neutral and the rev cycle with continue until it eventually conks, but no problems on freeways or anything just driving slow.
If anyone might be able to shed some light to why my car might be doing this it would be very appreciated Cheers Nick

 

What engine does the car have? Could be an air leak problem, idler valve, water coolant sensor, camshaft or rpm sensor....pick one.

Also if yours is a 1995 model you could read off the fault codes using the blinkbox in the engine bay mounted on thee big black box on the right car side.

 

+1, what he said. What are the code(s)?

 

How to on reading codes using the under hood diagnostic panel by the washer fluid tank.
http://www.matthewsvolvosite.com/read-codes-volvo-850

The other way to do it is to have Autozone, Oreilly or ..... hook up their OBDII scanner to the port just above the shifter in the center console and do a free reading.

 

 

i tried useing that Code Finder next to the washer fluid, followed the video posted but it wouldnt give back codes like it did in the video it wouldnt blink or anything, i noticed also that my transmission fluid smell like burnt clutch could this have anything to do with it

 

IIRC, the interior courtesy lights need to be working. If the fuse for the lights is blown you might not get power for the self diag to function. Do your interior lights work ?? If all else fails have one of the auto parts stores do a free reading. BUT if those interior lights aren't working as in the fuse is blown , , , both diag units should be dead.

You need to do a drain and fill a couple times or a DIY flush.
This is Rspi (on here) video of the drain and fill.

Myself, I like using the transmission to push the fluid out and do it all at one time.
http://www.matthewsvolvosite.com/for...pic.php?t=8767

But , , , now you have choices.

 

Thanks so much for the videos and the replys i knew nothing about this codes system the volvo had and now i do, I just went for a short drive in the thing then, i literally had to feather the throttle the whole way home or the revs would just go up and the car would do nothing, like the clutch had slipped out, it was like i was bunny hoppin a manual, im thinking of making a video and putting it up on this page so you guys can see for yourself( i know my descriptions can be a bit vague) anyway in my eyes its starting to look like somthing in my trannys ****ed, that said i know **** all about volvos.
All the same loving the advice im getting and your information is muchly appreciated Cheers Nick

 

 

Does the Check Engine light work? Seems to me that you have a gross air leak or a bad MAF.

 

I've had this problem before, Bad MAF Sensor. Get it on Ebay about $20.00 and you can install it in around 10 seconds.

 

The poster has an N/A engine. The 10V version has no MAF sensor, only a temperature sensor. The 20V has a MAF.

@thread opener: which engine and model year is your car? 140bhp or 170bhp. 1995 and older or newer?