Rough Idle

[Adam_rex]

ok so my 240 went from driving ok to bad... it drives fine for the most part. but when i clutch it or just let it idle it wants to die. not all the time some times it idles fine sometimes it bounces from a 100-1500 rpm idle and other times it just flat out dies. i have put lots of injector cleaner in to see if that was the prob. but nothing. also it is always blowing black smoke. even at idle it smokes like this. so i was thinking its something with o2 or MAF but either one should be pulling up a code.

[240SXSlideStar]

What does "When I clutch it." mean?

[nissan_240sx]

I think that means when he pushes the clutch in.
hmm black smoke, hows you're oil? there are alot of factors that come into play for the idle problem.
-MAFS is faulty
-throttle body is sticking/dirty
-fuel filter needs to be changed
-adjusting your tps
-AIV needs to be cleaned
etc. search around, there are many 240 idle threads

good luck

-Matt

[Chuki_breath]

yea i was going to say aiv, but i dont know if that would cause smoke. Id replace it all anyways, since %99.9 there bad anyways. Fuel filter is cheap. MAF might be a little more expensive. Throttle body you can look at before you drop cash on. AIV you can do. All that shouldnt be to much cash. Then you shouldnt have to worry about those for a long while.

[R.W.240]

Black smoke should be something fuel related.

[Skylindrftr]

that happened to me when my filter fell off and the maf was pointing at the ground...but I ziptied it to my charge pipe so now its all good...i think its the maf in a lot of cases...check it

[driftjunke]

How many miles on you motor? Pull your plug, and check them see the condition and you can generally tell whats going on, Ever done a compression test? Might as well while you have the plugs out, just to check the condition of your motor, rings could be getting weak.

E

[dimitri_]

What does it do when it's idling and you give it gas?
Do the RPM decrease instead of increase ?


If they decrease check for a leak in the rubber boot connecting the plastic air intake hose, (running accross the radiator), to the throttle body.

it's hard to see in the creases until you remove it and bend it to see in the creases.

Around $80 from the dealer or RTV and duck tape

[D-Bo]

sounds like you gotta tune it up a little.. check your fuel pump and filter (pump is in-tank and filter is on the passenger side of the engine bay.. to check your pump, go to a quiet place, turn everything off, and turn the key to 'on' and see if you hear the pump), then take your mafs off, clean it and see what happens. for your fuel filter, i'd suggest getting a new one. even a new oem filter will make a huge difference. and they're cheap too. you could also make sure you don't have oil leaks.. pull your plugs and check them.. i don't know what else..

[Adam_rex]

yea i have done most of this when i bought the car. but sounds like i need to do again. and motor has 113k i think when i push gas it runs fine. it only has a prob with idle. and it burns gas. bad. my milage is shit right now. i think its my MAF. but ill look into some of these other things as well.