Hi,

Just bought 3 weeks ago a 2000 Maxima GXE with 45500 miles on it - my first car . After I left it at an airport for a week, i got a SES light
and noticed rpm fluctuation at idle. I took the car to the dealer and they "fixed" the light. I dont know what was wrong since the guy wasnt there when i picked it up (the other guy said "probably oxygen sensor"). But the rpm fluctuation remained. The pattern is like this:

Every ~2 mins it drops to a about 510 and car shakes a little a couple of times and then goes up to 550. This is more pronounced when the engine is cold. When the engine is warm all i can feel is occasional slight roughness. I changed the stock airfilter to K&N and filled the tank 2 times with injector cleaner. I also took it to a non-dealer mechanic and he found no obvious problems with the car, but regapped the plugs.

It also seems to eat a lot of gas. I estimate I get about 10 mpg. It seems low even for driving in the city in cold weather. Other than that it does not seem to have any other problems.

Do these simptoms ring any bells? Any recommedations, suggestions?

Thanks,
Tim

 

i know you said they removed the cel but has it returned at all? sounds like it could be bad coil(s). do you have any issues with acceleration where it wont go past a certain rpm? if the cel is on, id take it to autzone and them pulled for free.

 

Check Engine light did not come back. I dont know if there are acceleration issues as I dont get a chance to accelerate that much in the city. Would it be the same if I test it by revving it on neutral?

Tim

 

actually, im not too sure if it will work in neutral or not. my first thought is that it would have to be in gear but im not positive. i would tend to think its coil(s) if the engine has no problem with reving over 3k.

 

If the idle is the ONLY problem. I'd say get that checked/adjusted. If its is accompanied by power loss throughout the rev range, then your MAF may be going bad and/or your coil(s).

TK

 

Yup, your right. Either the MAF is bad or the coils. I'll put my money on the MAF. It has more to do with the idle.!!!!!!!!!!!!!!

And beside, if it was the coils, you would feel something wrong in any rpm.!!!!!

 

Whats MAF? cause today in cold weather i had the same problem the car has droped rpm's and when i hit the gas the exaust feels like it has backfire with air and doesnt' have any power

 

Mass air flow meter. It costs roughly 70-80 dollars new at a dealership, or at least thats how much I paid for mine. If the problem is indeed the MAF, go get it fixed quickly. A bad MAF when left alone, could lead to coils going bad. I waited too long to replace mine and my number 3 coil went bad, along with the rear o2 sensor. The O2 sensor was just dirty, but its still a P.I.T.A.

TK

 

Would that cause low gas mileage? Or which one is more likely to cause low gas mileage?

Tim

 

Its MAF, I had the same problem told it to the stealership who charge me around 300 to fix it.

 

I seriously doubt that the MAF sensor has anything to do with the coils failing, FYI...

Now the O2 sensors being dirty (from running too rich/improperly), that's a more plausible theory.

 

I have the same problem, some times the idle drops so low it stalls, but this is only in the morning, or after i havent driven it for a while. My mechanic mentioned somting bout the 02 sensor also along wif the Fuel and Intake sensors. Im goin back on Wed. cuz it jus started acting up again after 3 weeks. I keep you updated.

(I started another thread about this prolblem, did even get 1/3 of the replies...)

:attention

 

I have the same problem also. My idle is a little unstable for a brief moment, then pops back up. I can't figure out what is wrong with the car. I changed the plug, fuel filter, pcv, and air filter. Nothing solved the problem. I don't think that it is the MAF sensor because it would throw a SES code.

Also, my car has a hesitation between 2-4k rpms.

 

MAX2000JP: DO NOT BE FOOLED. Everyone on here talks about MAF failure and how it will throw a CEL. Not always. If the voltage is fine, you will never get an SES. I had serious power loss, and the car felt like it stumbled between 3000-4000 rpm, but it wasnt a stumble, what was happening in between those RPMs was the MAF was crapping out, and it was ACTUALLY affecting from 3000-redline, but the most noticeable change would be at 3000-4000 where it would stumble. It only feels like its stumbling at 3000-4000, but its actually losing power from 3000-redline. I had no SES at all. Car would have some idle issues as well, the worst being under very light throttle on a cold engine. I see you're in Chicago area too, shoot me a PM if you want more description of what problems i had, I'll tell you all about it.

TK

 

UPDATE: Yesterday I drove to Atlantic City (from Brooklyn) and back. This was the longest trip ive taken the car on so far. On the way back ive noticed that I dont get the rpm drops anymore. When I start up the engine the rpms go down smoothly to about 510-520. I still feel slight roughness on idle. I think it could be due to low idle rpm, since I've heard it should be around 550. Go figure...

Tim