Romeo

my maxima is a little sick

here are the symptoms:
- very rough idle. it is at 700 RPM and idles like i have a really aggressive cam (it lobs and jerks and shakes the entire car)
- when i let off the brake and coast in drive (yes, my car is an auto) it jerks and putts along. only when i apply gas will it somewhat stop
- loss of power
- NO CEL

car has had these symptoms for a week. it stopped for about a day or two and than started back up again. my guess is it has a dirty fuel filter which i will change tonight. but could i be misfiring in a cylinder? what would cause this? bad plugs?

thanks

maxspeed96CT

iTrader: (9)

It could be one of your sensors my car was running real funny because when i got my intake i didnt ook up the intake temp sensor corectly.

njmaxseltd

iTrader: (19)

No CEL huh?

Could be a clogged injector. Take your plugs out and look at them. See if you can identify the cylinder thats misfiring.

Tactics

I had this problem once, was one of my heated o2 sensors. They did not light up a CEL either.

Tactics

iansw

iTrader: (7)

Do you have alot of black smoke/fuel smell coming from your exhaust??

If so, then it's your MAF.

Romeo

ian: no smoke or anything. i went back and sniffed my exhaust and i don't smell any excess fuel

my intake temp sensor is fine. its plugged into my intake and looks to be in good condition

my MAF is also plugged in and fine.

a bad O2 sensor would most likely trip a CEL. actually, from all the post i read, it should atleast give me a 0304 (knock sensor) trouble code. but we all know the story behind that.

i'm selling this car to a really good friend of mine and would like to give it to him in excellent running condition. if i was trading it in, i wouldn't really care. on another note, after i noticed the problem, i put a bottle of fuel injector cleaner in it and a few days later is when i noticed it had stop. i told a mechanic about it when i went in for an oil change and he said everything including my injectors looked good to go. he said it might be my intake setup. i'm running a "short ram" set up. he said it could be a leak but that would not account for the symptoms, would it?

Tactics

I know a couple of people that have had bad 02 sensors and no CEL

Tactics

Romeo

you're right, its usually an O2 code with a knock sensor code. damn new cars and all their sensors. i'll spend $200-$300 fixing this car before i sell it.

also, i had a misfiring cylinder in my old max and that did give me a CEL.

Tactics

Also, when I thought my max was misfiring, it really was firing, but really really rough. Probally some horrible timing problem due to the fried sensors. You might want to check for ECU codes regardless of a CEL or not. Just a suggestion.

Tac

Miasma

so what are the symptoms of O2 sensors that are on the verge of dying if you dont get a CEL yet?

Tactics

I'm not an expert, but I'm willing to bet like most electronics a sensor is either working or not.

However, I know if they get dirty or some carbon build up on the sensors your gas milage could go down, or you might feel a slight loss of power.

just my thoughts
Tac

Miasma

i just did the 'chilton check' for resistance across the two far terminals and no continuity between either outside terminal and the center terminal. both sensors checked out fine.

ericdwong

I too am having trouble with my car idling funny. No CEL light, but it did before, it identified the 3rd cylinder (center in the back). I swapped the coil to the left and the plug to the right (plug was carbon fouled) and the CEL never showed up but the rough idle is still there. I changed the plug that was fouled and it still idles rough. I did the pull the coil pack test and each one still makes it idle rough. I gotta test the packs and injectors individualy.

Romeo

at the risk of starting a flame war, i am beginning to understand your point of view with maximas. i've had two and if its not one thing, its another. O2 sensors, knock sensors, alternators, starters, tranny problems. some people have had good luck from the start. others (the majority) will run into problems. my mom's maxima is babied and already had a knock sensor go out and a busted tranny (both covered under factory warranty).

back to my original post, after searching some more, there is a number of things that could be wrong besides a misfiring cylinder such as EGR, IAC, throttle body, vaccum leak...this is going to take me forever to figure out.