I have an 04 xA, Automatic, with about 45 thousand miles on it. when im sitting in park or in drive with my foot on the brake it sits at its normal idel which is like 700 RPMs, but then it will dig down to about 500 to 400 RPMs and the car shakes abit and then it goes back to normal, but this has been happening abit more lately.

My question is what do you think it is? I thought it was the Fuel Filter, but I found out they are in the tank and those rarely ever get dirty. so anyone with the same problem or knows whats up and could tell me would be awesome. Thanks.

~NOLA_xA

air filter, change your spark plugs, keep up with your oil changes? running lots of accessories like lights, speakers, a/c?

well, i thought it was my air filter, and i changed that and it didnt help. i havent changed my plugs since i got the car which has been 2 years. i dont have any body lights or anything, have nothing but stock audio as well.

check your maitenanace guide, i think your supposed to change the spark plugs at 30k miles on the xA/xB engine.

also, you could try just resetting the ecu by disconnecting the battery for 10 mines, then reconnect it and let it idle for 5 minutes to reaquaint itself.

ok, i'll try that and see how it does and i'll let you know. thanks for the help.

Would seem like the spark plugs, I would have said you might have a dirty air flow sensor. You said you have a stock audio system, but do you have a stock motor? Oh, I've read that people who installed the ground wire kit with the automatic have had a better idle, just something to consider.

Mine did the same. I reset the ECU by pulling the fuse for 10 minutes, put in Irridium spark plugs, switched to full synthetic oil also (doubt that's gonna help, but....). the plugs really helped stabilize the idle. Also got Randode's ground wire kit, but haven't had time to install.

yeah, i would recommend disconnecting the battery for a bit and then reconnecting it and letting the car idle for a while...did you recently have to disconnect the battery for anything/install?

change the spark plugs make a ground wire kit and change ur air filter

buddhas yeah, i had to when i installed my fog lights, would that have affected anything?

and do ya'll have any suggestions for the best spark plugs??

denso iridium are the best around.

and yes, your foglgiths could be a problem if they aren't grounded right, and causing a problem i would think (not really an electrical expert)

buddhas yeah, i had to when i installed my fog lights, would that have affected anything?

and do ya'll have any suggestions for the best spark plugs??

yeah, they're probably not grounded properly...and another thing is once u disconnect and reconnect the battery terminal...you must let the car idle for about 15 minutes so that the computer can reset properly

Is your A/C on?

I have an 06 manual and mine has done this too. It's only been a couple times when I was sitting at a light and changing the vent settings. It felt like the a/c compressor kicked in and the ecu didn't correctly compensate for the extra load. RPMs kept bouncing between about 500 and 750 RPM (normal idle is about 650). My solution was to not mess with the vent settings while idling sitting (or slowing to stop) at a light. It hasn't done it since.

yeah, mine has now stabilized. i got NGK Iridiums and reset the ECU, and it has all settled down. so i appreciate all the help.

i just ordered an new grill, really excited man. ill post up when it comes in and i get it painted an put on. again, thanks for all the help.