Rough Idle Questions??????

[alexB]

Ok so I need some help from ya guys. I am not totally sure. Have a few ideas myself.Whenever I start my car up it the rpms dip down and then jump back up. This started alittle over a month ago. Seems to be happening more often now. Today it started to jump up and down non-stop at a stand still. It seemed to not do it if the car was being driven for a while. I did just have my mass air flow sensor relocated but this problem seemed like it was there just a little bit before I did that.

1 - I think I may be running very rich (thought relocating would lean out if anything though)

2 - Maybe the mass air flow is already starting to have issues.

3 - Possibly a boost leak somewhere( Not sure where to look)

Anybody have any ideas????? Thanks for anykind of help. I greatly appreciate it.

[Raider]

I have seen this before myself, when the EGR valve gets stuck due to carbon buildup. The EGR is a PIA to get to without removing the battery. It is mounted tothe bottom of the throttle body, 2-12mm bolts that were put on with a ton of torque. There is an electrical connector that plugs into it. Remove those 2 bolts, There are 4 really soft metal phillips screws holding the electrical part to the valve itself. Spray some PB Blaster on them to get them to come off easily. Once apart, clean out the valve with a carbon buildup remover solvent. Clean it up, put some oil on the spring, and reassemble. might even want to reset the ECU after the process, and seehow that goes.

[Boostd 3]

is there a CEL on at all? The problem that you are having def seems to be a sensor, either an O2 or MAF or EGR. Has it stalled at all? Something else you may want to try is cleaning the throttle body. If you get alot of carbon biuldup in the tb, it will also cause a rough idle, don't know if it would make the idle jump like that, but it is worth a shot. If it is, go to Advanced Auto Parts and get Valvoline SynPower Throttle body cleaner, best **** on the market, probably $6 or so, and a soft tooth brush. Spray a little bit in the tb, with the butterfly open, softly scrub the walls of the tb. Don't spray too much or the car will be very hard to turn on.
Another thought, did you disconnect the battery when you relocated the MAF. If not the ECU will not let the car run right. It is getting new info on an old setting. Disconnect battery, turn on headlights and reconnect. ECU will relearn new info. Just a thought, let us know what happens.

[Cullen]

I put money on a leak somewhere. How does it run under load? Or are you only having idle issues in neutral?

DESCRIPTION
Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.POSSIBLE CAUSE
Vacuum leakage
IAC valve malfunction
Air leakage from intake-air system
TP sensor or related circuit malfunction
MAF sensor or related circuit malfunction
Brake switch or related circuit malfunction
Neutral/clutch switch or related circuit malfunction (MTX)

[alexB]

No I am not showing a cel. It hasnt stalled before. Yes the idle issues seem to be in nuetral now that I think about it. I did take the throttlebody off to install the rear mount. But I think this problem was already there before I did that.


I think I might try and clean the egr.

[StreetUnitMike]

No I am not showing a cel. It hasnt stalled before. Yes the idle issues seem to be in nuetral now that I think about it. I did take the throttlebody off to install the rear mount. But I think this problem was already there before I did that.



I think I might try and clean the egr.


Let us know how it goes!

[stevEvo8]

How old is this car?

What you are getting sounds like idle surge.

[Mrs. AlexB]

How old is this car?

What you are getting sounds like idle surge.

the car is a 2003.5 what do you mean idle surge?
it idles up and down, is that what you mean?

[stevEvo8]

Yes,

Is it NA or turbo?

[Tyler]

I had the same problem w/ my Pro...cleaned the hell out of the EGR and TB general area, and the problem went away...Hopefully this will be your solution as well! Let us know :)

[alexB]

I had the same problem w/ my Pro...cleaned the hell out of the EGR and TB general area, and the problem went away...Hopefully this will be your solution as well! Let us know :)
I plan on trying that..... But first I am gonna mess with my BOV settings and replace most of my vac lines. Hopefully one of theese will solve it.

[stevEvo8]

Is your car under waranty? Take it back and have them figure out what is wrong.

As for the idle surging. I know that the mitsus have a BISS base idle set screw on the throttle body. sometime the seal around the screw wears out and allows the idle to surge like this.

Does this happen under decel and does your car stall under decel? Are you venting to atmosphere or recirculating. Do you have a relocated MAF? Is you MAF dirty or damaged?

I would zip tie all of your vacuum lines while you are checking them. Also check your IAC.

[stevEvo8]

You may also want to check this out.

http://www.4g63hp.com/forums/showthread.php?t=4111&highlight=seafoam

[Slowp0ke]

could be a spark plug fowled out?

[alexB]

could be a spark plug fowled out?

I just put some in about 2-3k miles ago. Guess it wouldnt hurt to replace thoose again.

[alexB]

Is your car under waranty? Take it back and have them figure out what is wrong.

As for the idle surging. I know that the mitsus have a BISS base idle set screw on the throttle body. sometime the seal around the screw wears out and allows the idle to surge like this.

Does this happen under decel and does your car stall under decel? Are you venting to atmosphere or recirculating. Do you have a relocated MAF? Is you MAF dirty or damaged?

I would zip tie all of your vacuum lines while you are checking them. Also check your IAC.

Warrant is pretty much bye bye. Got about 200 till I roll 50k. Plus I really dont feel like demodding my car. I know they would give me **** about it.

[Raider]

if it was plugs, the car would run like crap all the time, and not just have an erratic idle. The EGR being messed up is a VERY common problem with 3rd gen pros. Seriously, try that out first.

[jakemp3surfin]

did you find out the problem yet?

[MSP608]

you might as well get the 626 manifold haha

[computerGeek]

my car runs smooth as hell at idle @ 500rpms-ish

nology hotwires helped with that!

[Mrs. AlexB]

wow, i completely forgot about this. the weather here hasnt been that good so the car hasnt been driven much. we had a massive winter storm(imo) but i'll be sure to ask alex when he wakes up

[torresmsp]

you said that you had to take off the throtle body? did you replace the gasket at the throtle body? go to auto zone and buy a can of brake clean, while the car is on idle spray around the throtle body if your idle changes you have a leak there. also reset your ecu, and adjust your idle screw wich is right on top of the throtle body. good luck

[PlatinumMSP]

i bet its the wastegate, do the vacuume trick on the diaphram, my car had the same issue when my wastegate went out!

[alexB]

i bet its the wastegate, do the vacuume trick on the diaphram, my car had the same issue when my wastegate went out!

Well I tried that a couple days ago. Everything seemed fine. But yesterday on the highway I gave it some gas to see what I was boosting and it seemed to be getting higher. NOW I did just change spark plugs recently. I was due for a change badly too. I know that should make the car run better but I went from boosting around 6-7 psi to about 10 on stock boost. I am gonna just get a new wastegate. Sounds like that is my problem. Any opinions???????????

[Shakenbaby72]

your car sounds like its running like mine

[Raider]

Alex, Isn't your exhaust manifold cracked?

[alexB]

Alex, Isn't your exhaust manifold cracked?
Yes my manifold is cracked. I am now leaning towards the maf sensor. If that was totally bad would the car not start up? Yesterday I changed the primary O2 sensor and had it running. I also took my intake of for the hell of it to check for any shaft play. Today I put everything back together and triple checked everything to make sure I didn't forget anything. It wont start at all. I dont think it is my battery cause my AEM uego still lights up. And I have an almost brand new optima yellow top in my car. So could a bad MAF sensor cause your car to not start. It makes absolutely no sound at all when I turn the key over.