rpms dipping while idle

**brad995** · 01-05-2009, 07:44 PM

While I'm at a stop light or idle while in drive the car usually idles at 700-800rpms and it drops to about 500 (maybe even a little less) and it feels like it's going to stall but it never does. The rpms then go back up to normal. It also happens while I'm in park but not as much (or i just don't notice it).

What could be the problem that could be causing this? I have had a battery terminal problem that the negative terminal has a small crack where it connects to the battery but it has been fine for months since this, could it be related?

The check engine light is not on and the car is running fine besides that.

I have a 2001 4cyl with a CAI.

Thanks for your help.

**qnz** · 01-05-2009, 11:16 PM

my guess is vaccuum leak. do you have an aftermarket intake? check the elbow to the throttle body. thats where mine used to get lose and i would have the same thing happen.

**brad995** · 01-05-2009, 11:30 PM

Originally Posted by qnz

my guess is vaccuum leak. do you have an aftermarket intake? check the elbow to the throttle body. thats where mine used to get lose and i would have the same thing happen.

Sorry to be a noob but whats the throttle body?

**8g831** · 01-06-2009, 02:09 AM

im having this same thing happening to me but just at park..and my dash flickers too..

**starh4x** · 01-06-2009, 02:12 AM

After I bought my new battery I noticed the rpm surging up and down for a few minutes.

**ricky_db** · 01-06-2009, 02:23 AM

mine used to die at stop signs, went to firestone and got a fuel system cleaning (not that stuff u buy and just put in the tank from wallmart) been good every since 8)

**8g831** · 01-06-2009, 02:27 AM

Originally Posted by ricky_db

mine used to die at stop signs, went to firestone and got a fuel system cleaning (not that stuff u buy and just put in the tank from wallmart) been good every since 8)

yeah they recommended me that when i went in today for some work..i think imma end up gettin it depending what my savings is looking like lol

**mitsu_vic** · 01-06-2009, 09:16 AM

A throttle cleaning may help.

**99 galant** · 01-06-2009, 09:32 AM

mine did this for a few days then stopped. not sure why

**Galantfan88** · 01-06-2009, 10:05 AM

Well if you have a 4cyl the black thing in the back of the engine is you intake manifold, when looking at it, going to the right of it at the end of that intake manifold is a nice silver box looking thing called the Throttle Body. This is also connected to you intake, which is that black long thing next to the battery. Did I do good?

**Galantfan88** · 01-06-2009, 10:05 AM

I suck at life.......

**juan18_c** · 01-06-2009, 10:55 AM

hmm i heard from a random dealership mechanic that all mitsu's after certain age they start doing this... my ride does it as well, but it only happens when driven for 1 hour+.

**qnz** · 01-06-2009, 11:11 AM

Originally Posted by brad995

Sorry to be a noob but whats the throttle body?

just tighten and check all the couplers for your CAI.

**qnz** · 01-06-2009, 11:17 AM

Originally Posted by starh4x

After I bought my new battery I noticed the rpm surging up and down for a few minutes.

yours is happening because when you disconnected the battery for a few minutes, the ECU forgot how to breathe. When you started the car up, it was re-learning how much air it was taking in. Thats why people reccomend disconnecting the battery for a few minutes whenever you install an intake. Intakes allows you to get more air than stock so your car should forget the old stock values and learn the new

**brad995** · 01-06-2009, 02:15 PM

Originally Posted by Galantfan88

Well if you have a 4cyl the black thing in the back of the engine is you intake manifold, when looking at it, going to the right of it at the end of that intake manifold is a nice silver box looking thing called the Throttle Body. This is also connected to you intake, which is that black long thing next to the battery. Did I do good?

I always called that the MAF. I'll tighten everything tomorrow because it's freezing today.

Thanks.