I'm having some problems with my idle. I have a 99 auto. The problem is intermittent but usually starts after the engine warms up. It happens at stop signs and stoplights. The engine starts jerking which makes the car vibrate. The rpm bounces from 700 down to maybe 550 then comes back rite away to 700. It happens when the A/C is on and off. The dealer says they cant find anything until the CEL goes on or if i can simulate the problem for them but the problem does not occur all the time. I had a mechanic from a local auto shop who said it might be misfiring. Plz help, no1 seems to know what the problem is.

 

Throttle Position Sensor or Coolant Temperature Sensor may be the source of the problem...

White96MaxSE

 

I have the same problem, have yet to find the answer, i've had it for so long I'm almost getting used to it. Just cause there is no CEL light doesnt mean you can't check it. I've changed spark plugs, 1 coil pack, fuel flter, knock sensor, oil changed, and air filter (cone intake). AFter all that, it went away but then it came back again. These are my symptons, tell me if they are like yours. When idling, my rpms will "jerk or bounce" causing a hard slight shake in the car. I have sluggish accelration and feel a loss of power, and also bad gas mileage.

 

You guys that are getting this should check your ECU codes. Either of the two above could be the culprits but I'd put my money on the Reverse/Neutral (5spd) or Park/Neutral (I believe this is the name in an auto) sensor. These throw codes but don't trip the CEL/SES light. You should also look for a sticking throttle cable/spring and lube it if needed.

 

i have a similar problem with my I30...when i pull up to a red traffic light and wait there, half of the time, the seats in my car feel like they're massaging seats. My TB is clean, had the EGR changed, idle screw was adjusted, IACV was cleaned out, knock sensor was changed, changed PCV valve. For now, I resort to using the ECU reset screw to bump up the idle a bit (all this does is mask the rough idle). By the way, my ECU throws no codes at all. ONly thing that is different in my car is that the RPMs dont jump up and down like yours, they stay constant (in drive/reverse with headlights/fogs on, i'm usually around 600 or so). Its nice to have massaging seats, but a luxury car shouldnt be doing this involuntarily!

 

by the way...i wonder if that recent post about re-grounding the middle MAF adaptor wire harness would solve the problem...or possibly another sensor's harness could be re-grounded to solve the problem?

 

I tried regrounding the wire, still have problems, not muchb the rough idle, but still slow accelration and loss of power. BTW, I do not have any cel light, and I check my ECU all the time just to do it and I have no codes (05 05). Whatever I have is not only giving me weird idle, but all the other stuff I mentioned too. I'm goign to do this in the next couple of days/weeks: change PCV valve, take off upper intake manifold and clean it thoroughly, try and clean EGR valve, add a Air/Fuel Ratio gauge to see whats up with my mileage. :P

 

Same problem here guys (funny idle). I've done and changed alot of things trying to correct it to no avail. My ECU has no stored codes though which makes me and the techs where I work (Nissan Dealer) baffled. Noticed it starting happening after my MEVI install. Like I said, I checked EVERYTHING from vacuum leaks to changing the IAC to resetting the TPS and base idle. Symptoms always come back and seem worse when the car is not up to normal operating temps. When I step on the gas, tho, the car will light the tires and perform like a champ. Figure I'll be able to nail the problem when I get my new car in a year (be able to tear down the Max for a rebuild).

 

What about the two Crankcase Throttle Position sensors?

Vacuum leaks?

Intake Air Control Valve?

Only Food for Thought.

White96MaxSE

 

Wouldn't know where to start to check these things

 

http://www.vbxmaxima.8m.com/tps.html for the TPS.

IM me if you want help with anything else.

 

Did you replace your ECTS? It is a $20 part and can give erroneous readings without the CEL going off. Consider it if you have problems when the car is cold. Most have hard starts and car running poorly when cold.

 

Cool. I will def try that then. Thanks for the idea.

 

ECTS?

 

Engine Coolant Temperature Sensor

 

I was thinking that that may be causing a poroblem on my car. Got to check it out.

 

I am almost 99% certain this problem in my max IS the throttle position sensor (my last stored codes were for the TPS, by the way...)
I'm having the sma problem and will fix as soon as I have like 80 bucks.

 

the weird thing is, i have no loss in power and my mpg is 23 rite now. the car doesnt vibrate so much that the car becomes into a massager its noticeable but not very violent.

 

sit in mine, and you will be relaxed with a nice massage while waiting at the red lights...i swear, its JUST like those pads or recliners with a handheld massage console that you find at Brookstones and Sharper Image!

 

there is got to be a way to fix this. My car does the same stuff. I have fairly new spark plugs, I don't want to spend any more bucks on any unnecessary changes. It sounds like a misfire at low RPMs. Could it be the ECU???

 

Muck with the throttle cables and that rocker arm they work on. Check the freeplay in CC and throttle lines. Change the PCV valve.

 

OK, Guys I changed my spark plugs today to bosch platinums, (I had Denso before) and now it misfires like crazy. Also my CEL came on, I got codes for Cyl 1 misfire and either throttle pos sensor or knock sensor im not sure about the last code, but I'll get those changed. let you know if it stops after that

 

BTW what is the normal idle speed for a maxima??? i jump from 800 to sometimes below 400 back when it did it before it was my altinator going bad but its just started up again about 6000 miles ago

 

Take out those Bosch Plats and get some NGK's. Also, check connections to coilpacks and stuff.

 

I took my Max to the dealer today, they checked it out, as it turns out I had a bad coil on cyl. 1, and Bosch spark plugs that will not work good in maximas. The mechanic told me that Bosch spark plugs are high resistance plugs and our coils are not fit for that plug. I got 6 new NGK's one new coil, I'm 280 dollars poorer, and my maxima is good as new

 

Bocsh spark plugs suck, we all could have told you that. Why did it cost you $280? 6 NGK plugs cost you about $60 bux, and you could have put them in yourself. =/

 

It cost me 280 cause the dealer charged me 90 bucks to check out what was wrong with my car, 90 bucks for a coil, and 6 plugs for 16 bucks a pop. I changed them my self, If i didn't they would charge me another 100 bucks

 

cant you pull the codes off an ECU of a 99? i thought they changed it for 2000 and after (took out the screw from the ECU), or am I wrong? could have saved you the $90 diag fee (which i think is still high...i thought they usually charge you one hour of labor for diag...which is around 70 bucks). otherwise, i believe autozone and other places can pull the codes for you if you dont have the screw in teh ECU.

 

I may be way off with this but it is an idea. My mother's Chevy had a rough idle only when the car was stopped and in drive. Other than that the car ran fine. She had tune-ups and mechanics could not find any thing wrong. It turned out to be her motor mounts.

So check you motor mounts. Just an idea. Please don't flame.

 

I have the same problem and I'm in the same situation as most us...no codes, I had the 60k tune up...motor mounts hummm maybe. Has anything worked for anyone?

 

Im not sure if its motor mounts, because my idling is jerking..like sparatically. Motor mounts would make the engine/car shake in a different way in my opinion. Good thought though.

 

I just got NGK plats for $37 shipped

 

Hey, Join the Rough _ Idle Team.

I spent $hundreds$ just Trying To fix it. Good Luck!

 

Did you fix it? Im still in the process...looks like I will finally have to give in to going to a dealer. =(

 

I have similar problems. I also have a SAFC that tells me the trottle position at all times. The interesting thing is that sometimes when the car is at idle, the reading is 0% but other times it is in the 1-3% range. Could this be a sign of the TPS going bad?

 

Im going to check my TPS too, oh how I wish hat would solve all my problems =/

 

New problems guys. Today I had my y-pipe along with fuel pressure and egt gauge installed. After that my mechanic adjusted the screw onthe IACV so that it would not click every second. However no the idle is around 550, and whenever I come to a stop my rpm drop to around 400rpm before the computer catches it. WTF is going on and how can I fix it?

 

I would just turn the idle back up to a level where is doesnt bounce like that.

 

But then the IACV will click again and I know it should nt click. Plus everytime I look at someone elses IACV who have no problem, the screw to adjust the IACV is on the same levcel as it is set right now. Why is my engine dipping like this. I might just go back to having it click.

 

I have some kind similar problem, my car has rough idle, but this does not happen all the time. a lots of time the car runs perfectly fine. but sometimes the rough idle comes back. i have done everything that you have done... beside changing any of the coil packs. But i don't know why my maxima does that. could that be bad IACV sensor. it seems like to me the gas and air not mixing very good. what could cause that?? anyone knows????