my z has be acting funny recently, at first i thought it was because of the cold weather here in jersey but its just so bad it cant be. i have an 03' so the DE motor and my car sparatically fluxuates idle and almost shuts down its so bad. no CEL comes on even while its happeneing. the car has become very jerkey when idle moves about and honestly just sounds like the motor is choking. i have 70,000 miles on the clock and am thinking maybe spark plugs, but im not sure because i have no CEL. !!!!Also when the car moves in idle and starts up it smells heavily like its rich... any ideas? please help guys

 

Looks like someone hasn't been staying on top of their maintenance. Your guess is as good as mine with the spark plugs. It could also be a fuel issue. Does it take a long time to start up? If it does it might also be the battery or it's connection etc. Car batteries with not much life yet start fading in cold times. Check those out first before jumping to any major conclusions.

 

well this z i got with 58,000 and i take very good care of the car but i just cant imagine whats going on. you would think that even with a missfire from a fouled plug it still manage on five cylenders and give me a check engine light but nope!... odd thing is its random. not constant and happens sometimes after driving fine for 20min. i cant pin point it and id really rather not drop it off to someone and spend mad loot guessing whats wrong.

 

i have another z that has never had this issue or anything like it

 

Just check back on those things to make sure. Also I think there might be a fuel problem by the sound of it. Idk, I'm not a mechanic. I've also read about some people not putting on their throttle position sensor back on correctly or it would be dirty which would cause the car to act funny. It would tell some sick eddie murphy jokes and knock knock jokes. But in all seriousness, check those to make sure.

 

Maybe clean the maf and change the air filter.

 

^that too

 

you said

"Also when the car moves in idle and starts up it smells heavily like its rich"

If it didn't start, check plugs, but it does start and doesn't run well but you clearly get fuel, so O2 sensor it is.

 

With a 2003/350z and 70K+ miles, the first thing you want to check is the camshaft position sensors and the crankshaft position sensors… in your case, either or both need to replaced.

Your O2 sensor is probably OK. The O2 sensor reports “bad” when the camshaft and/or crankshaft sensor report a problem.

--Spike

 

Those wouldn't show up as service engine soon light come on? How much will replacing both cost to replace?

 

Spark plugs would be the easiest thing to throw at it. Does it do this all the time or just at idle? If it smooths out when you're driving it could be a vacuum leak. Hard to say whats wrong without more information

 

I'm thinkin its a cam position sensor going bad.It won't give you a CEL.
It will screw up your cats.

 

I would start simple if I were you. Check for codes with a scanner, even if the CEL light is off. Fat chance of it being the plugs or any sensor, if there's no codes. Misfire codes with cause a flashing CEL instantly.
Start by adding a bottle of dry gas.

 

happens randomely

 

this may explain the smell i was talking about

 

ill check it tonight

 

I know Spike is going to bust my chops about the dry gas, but you have cold weather, no CEL, and a car that's not running worth a crap.
For 2 bucks, you can put in the dry gas. If it doesn't work, you'll know to look elsewhere.

 

thanks man

 

Actually, I agree with myfirstzcar (i.e., do the $2.00 fix first). If your gasoline does not contain any alcohol (Minnesota has E10 gasoline which is 1 gallon of ethanol every 10 gallons of fuel), adding alcohol to your gas tank is wise. This makes the water from condensation miscible so that it does not freeze in your fuel line.

If that doesn’t do it, have a Nissan dealership run your codes (emphasis on Nissan dealership). I’ll bet you have a problem with your camshaft or crank shaft position sensors.

--Spike

 

UPDATE!!!! CEL P0305 cylinder 5 misfire! SCORE!