Idle issues

drew525 · Post by **drew525** » 27 Dec 2008, 13:35

I'm having an idling issue with my 850 R. When I start it, it seem to idle rough and the rpm doesn't stay constant. When driving it stutters a little bit when accelerating but performs okay at higher rpm's, the stutter resumes when the rpm's drop. It did throw a CEL and the codes were 0303 and 1310 which I wasn't surprised to see indicate a misfire. The plugs have been replaced within the last year and the wires were done about 3 months ago. Any ideas? I'm thinking the MAF could be a possible cause.

Post by **MadeInJapan** » 27 Dec 2008, 15:56

Big (and important question here): Which plugs and wires did you use?

drew525 · Post by **drew525** » 27 Dec 2008, 16:10

I used oem plugs and wires. It was the first time I had used oem plugs as I usually have only used NGK. I didn't replace the cap and rotor when I did the plugs as they were done not to long before.

Post by **MadeInJapan** » 27 Dec 2008, 17:25

So, I assume they were gapped correctly too (0.028 inches)?
Can you describe further your the missing at low idle....certainly could be a MAF starting to go. Have you attempted to clean it yet?

drew525 · Post by **drew525** » 27 Dec 2008, 18:01

I'm going to clean out the maf tomorrow. As far as describing the conditions the rpm just doesn't seem to stay constant at idle, it drops and the engine starts to shudder a little almost as if its going to stall but then the rpm returns to normal. This cycle continues while the car is idling. Something else I noticed is that after driving the car for awhile the problem seems to go away, I can then put it in park and it idles fine.

Post by **MadeInJapan** » 27 Dec 2008, 21:10

I would check out the butterfly opening on the throttle body- these can get dirty and do what you describe- Under heavy throttle things seem fine...then the butterfly should stay mostly closed, gunk in it keeps it more open than it should be, causing strange idle issues.

Post by **Ozark Lee** » 27 Dec 2008, 21:33

While you are working on the throttle body also check and clean the IAC valve. They tend to gunk up with greasy residue and then they get stiff in cold weather and don't regulate the air flow properly. Brake cleaner has worked well for me in the past to clean up the IAC valve.

...Lee