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View Full Version : 05' 545 - car surges a bit at idle, normal?


boost7
07-17-2012, 12:35 PM
At a stop my car would idle about 500rpm but surges a bit and rpm drops up and down. It doesn't seem normal and a bit more noticeable this morning. So my question, is this an indication of vacuum leak or something more major? Has anyone else had the same issue. I thought the car was going to shut off at once, but it picked back up. Other than that, it drives fine.

Plugs has already been changed 4k miles ago when I first started noticing it, but now it's starting to get worst.

I'm not too familiar with this car as I'm fairly new, so please chime in if you have any advice on what to look for.

AndrewK
07-18-2012, 01:22 PM
Do you notice it only happening with the AC on? My car always "bumps" when I'm at idle and the AC is on. I have tried turning the AC off to see if it still does it but it goes away. Then as soon as I turn the AC back on it starts happening again. It is intermittent and not a continuous pulse, rather an inconsistent and random bump. The RPM dips a little when it happens. It is VERY VERY annoying but doesn't seem to affect driving performance. I would love to know where this is coming from and how it needs to be fixed. Hopefully some additional replies from other users with some advice????

boost7
07-18-2012, 02:50 PM
It does surge a bit more with the A/C on. But my car now at normal idle has a lumpy feeling like the motor wants to turn off, so I'm thinking something else needs to be replace or repair.

dolfan13
07-19-2012, 01:14 PM
I read about a program change to the valve lift with the A/C on.Have not followed up myself.

AndrewK
07-19-2012, 01:49 PM
What did you read and can I find it somewhere?
I've looked at other similar discussions about this issue and my first step is to try Top Tier gas and use a fuel injector cleaner or something of that nature (Techron perhaps?) I want to do cheapest options first, and some people have said those two things fixed their problem. Fingers crossed...

boost7
07-19-2012, 09:21 PM
I think my car is just thirsty for more money

borderchris
07-19-2012, 09:29 PM
Normal idle spec is 500 rpm with no A/C, per the book. A/C on is 700 rpm. But it shouldn't be hunting between the two.