KS, MAF, or something else? I'm stumped.
 

Lately I have been noticing that when sitting on red lights that my RPMs drop 100-200 rpms and then go back up to the regular idling RPM. It also makes little popping sounds out of the muffler and shakes the car every now and then very softly. This problem stops when car is in motion but in 2nd gears if the pedal is pressed more then half way it begins to jump a few times through 3-4k rpm and other then that runs fine. The other unusual problem is that it doesn't do it constantly but at random times, some days doing it all the time and others running completely normal. Does anyone have any idea on what this may be? I appreciate in advance for all the help.

a bad coil, check sparks, maf, bad injector check all that

while your at it , also check the camshaft position sensor , its on your left hand side of the engine if you are looking at it. Mine was bad and my car would drop down to like 400 rpms and then just shut down at the traffic light. Took me like a week to figure it out. Unless you have a SES for your MAF or KS , chances are , they are fine.

before you check into all these suggestions, which i might add are not bad ideas. i would start off simple first. is your cel light even on? have you scanned for codes? have you cleaned your iavc lately? is all your vaccums hooked up right?

^^^^^^what lock nuts said check all your hoses make sure they are free from kinks or leaks.

probably a bad coil thats starting to misfire.

sounds like a COIL or the cam shaft sensor..check it first

As far as codes there are no codes which just makes the troubleshooting more of a pain in the ***. I have a feeling its a coil too since it only misfires in 2nd but i will definently check all the hoses and the cam shaft sensor and everything else listed. I know its not the sparks because they are about 10 month old NGK iridium plugs.

I think it's the coil since its misfiring. Sucks that theres no codes, good luck though.

I'd put my money on coil packs since I had similar problems when I first got my car.

does it drop rpm just once, or over and over? if gotten hichups from cais before but it only did it once, coils and plugs for repeated dips

Its repeated. Yeah that's what im going with too.

i hate sounding like a donkey but most of the advice given so far would be incorrect. diagnosing a vehicle without proper information ie. OEM service manuals is pointless. you can drive yourself crazy trying to figure out drivability problems on your own. my opinion on your complaint is maybe you should go to a nissan dealer spend the hundred bucks or so and have them tell you the real source of your drivability problem and then if you can, fix it or replace the compenent yourself.

With the car running unplug a coil pack one at a time and reconnect, if there is no change in the rpm, when you unplug one, that's your culprit. You also have to consider the last time you changed your plugs.

That is the reason why he's on here asking questions. Why spend money for something you could fix yourself or diagnose yourself.

Sounds like a good idea, will try that out. My plugs where changed less then a year ago. Sadly I didn't get around to troubleshooting this problem yet as my clutch pedal went soft yesterday and this morning all it was doing was hitting the ground and i couldn't even switch gears. Bleeding clutch fluid in Fayes rain was fun but at least we finally got some pressure back in the pedal to where its driveable until I can get it to my mechanic who will check for leaks. Maybe time to get some SS lines. :naughty:

Yeah, spending a hundred dollars for a person to tell you whats wrong is kinda out of my budget at this point. Ima broke *** college student so the less money I spend on repair means more i can spend on new stuff for the car. I would rather play around with it and find out whats wrong.

I seem to have the same problem. RPM drops close to 300 and when i try to acccelerate it wont let me sometimes it just dies. It shakes some and then it dies sometimes the car tries to move forward but then dies. I do know that my drive axles are pretty bad. I was wondering if they get that bad would this be a problem or am i way off. I dont know much about coils or cars for that matter. but i did change the spark plugs about 3 months ago NGk's Iridiums gapped at .44 or something like that.
btw this my first post! :)

why spend the money? i would say that with the issue hes having fiddling with his cop system could lead to damage to either the cop or his ignition module.


if you really want to find the problem yourself n on a budget find your self a digital multimeter and a back probe(2 bux at autozone) and private message me and ill try and teach how to self diagnose.

here's a link to my thread - I'm having the identical problem and a lot of advice has been offered there:

http://forums.maxima.org/4th-generat...4500rpm-2.html

First of all, he doesn't have a CEL. The dealership is going to just charge him $100.00 then tell him that they didn't find anything wrong. I've been down that street. I've also fixed several cars over the years without taking them to the dealership, or using a FSM, as have a lot of people on this board. Just because you can't diagnose and fix a car doesn't mean only the dealership can.


Are you serious? The VQ doesn't have a "Ingition Module". It's a disrtibutorless ignition and it's controlled solely by the ECM, and you're not going to damage that by unplugging sensors/coils. Do you even own a 4th gen?

I have same problems. Thought they were related, but after I replaced the cat and y-pipe, the acceleration problem went away. The stop light stuttering remains, but I did notice that the grounding strap from O2 sensor was gone. Gonna replace that and see if it helps.

With regards to dealerships, 4 hours of diagnostics, they just shrugged.

i read somewhere on the net someone had same problem and they cleaned the throttle body and the rpm was kept up..im gonna be cleaning mine in a couple of days. maybe it could help solve your problem before you go off and buy more expensive parts to replace

TB was cleaned a few months ago so I doubt thats the problem, its leaning more to be the coils.

Had to get an emission's diagnostic, the tech adjusted the iac valve screw, starts up on the first turn every time and overall runs smoother.

Yup, sadly its not my biggest problem as of right now. I just put in a new Master clutch cylinder and slave cylinder a few days ago and my clutch pedal managed to get stuck all the way down on the redlight and i barely got it to the side of the road. Checked everything out and it seemed fine and it started back up but did it again 20 or so minutes later so i've been trying not to press the pedal all the way down on stops and hold it there which seems to be working but I have a feeling my clutch has gone to hell which sucks since it was replaced around 5-6 months ago with an Exedy. Everything seems to go to **** at once and when you're low on funds. heh.