It happens to me too. I just took off my Jacobs ignition , changed my plugs cap & rotor , and new sparkplug wires. It still does it though , but it does'nt do it every time like what it sounds like your having.

 

im gonna get new wires and spark plugs to see if that is the problem..its probably a good time to change them anyhow.

 

Your fuel filter is clogged.

Take it to a dealer, have them replace it. No more than $100.

 

uuuhhhhh yeah ok. how do you figure this one out? and why should i go to the dealer?

 

1st guess would be alt. 2nd guess would be fuel fillter and 3rd is always a charm ecu, I know sounds wierd but my friends 02 sentra had these same symptoms and the dealer mechanic said the ecu was the problem...but it was under warranty too.

 

ill test out the alt. later today when i get a chance. gotta wrap presents.

if its the fuel filter wont it work when at idle and bog out when you WOT???

 

My first question should have been whether or not it has a lope. You said the idle is low, but is it smooth, or rough? If it's low, but still smooth, it's NOT a spark plug (unless all four happened to degrade magically at once). If it's smooth, it's something that affects all four cylinders. Usually fuel delivery system is the culprit. Could be a fuel pump, but a clogged filter is about 10x more likely. It's not the alternator .. alternator won't do that. But if it makes you feel better, have it checked anyway.

All I'm saying is that smart money says check your fuel system. And you don't HAVE to go to a dealer, by all means, replace the filter yourself if you know how. Throw in a bit of injector cleaner while you're at it. What have you got to lose anyway?

 

NO. In fact the reason you don't notice it until the car is warm is because you'll only see it when the revs are low. When the revs are low, so little fuel is being delivered that even a slight change in fuel will alter the idle drastically (if regular idle consumes 1mL/minute, and you drop that to 0.5mL/min due to a clogged filter, that's a huge % change). In contrast, when you're at WOT, you're delivering a pile of fuel, so a small change in the amount delivered isn't going to appear noticeable (if you drop from a regular 20mL/min at WOT to 19.5mL/min, you ain't gonna notice ). When you first start the car, the revs will be up higher. Maybe 1200-1600, depending on how cold it is where you live. You won't see it then. When the idle drops down to 800 (where it's supposed to sit when warm), you'll start to notice it dropping off a bit.

If you're REALLY in touch with your car, you might be able to feel it at WOT or higher revs, but I couldn't feel it when I had the same problem.

You really have nothing to lose by checking it out. Even if it's not badly clogged, a new fuel filter is cheap as heck, and it'll improve your gas mileage a bit to boot.

(BTW, those numbers for fuel consumption may or may not be accurate, just used them for example. Too lazy to actually calculate real fuel consumption. It's easy to do, though.)

 

at idle its fine but when it starts jumping its rough. really rough. sounds like a motor about to be killed by releasing teh clutch (slowly) and not giving it any gas. but it doesnt shut off...

 

Probably just cause the idle's too low (ie, just like not giving it enough gas).

I dunno .. it could totally be something else. Bent valve, fried clutch, or worse. But those are pretty unlikely, and there's a pretty famous principle that says that whenever you have a problem, the simplest explanation is usually the right one (see Ockham's Razor ). Why go looking for a bigger problem when a 4-dollar bottle of injector cleaner might do ya?