Kehops

About 2 weeks ago I was driving down the highway in 5th gear when all of a sudden my car starts puttering for some strange reason. Not sure what to do I give it bit more gas and it seemed to take off fine as usual...strange. So I let off the gas and drop it down to 2500 rpm, at which point the puttering comes back, I give it more gas and it takes off fine again.

I get off the highway and come to a stop at a red light, the car is idling perfectly and no signs of anything being wrong are evident. Light turns green, I take off in 1st when at around 2000 RPM, the car starts jerking hard. So I give it more gas and it takes off ok, shift in 2nd and again the same jerking, I floor it and it's fine again.

This happens in all gears between roughly 2000 and 3000 RPM if I try to accelerate normaly. If I give it more gas than usual, I can avoid the jerking until I get up to cruising speed, at which point the hesitation comes back.

Crusing at 3000RPM will make it jerk but crusing at 4000RPM will not. IF I floor it too much it will jerk sporaticly throuhout the power band until 5500RPM when the jerking is too much and I have to shift. If I take it REALLY easy on the gas and gradually bring it up to 3500, it does not sputter.

I've had a check engine light ever since I installed my intake, but it does not throw any codes (0505). So I bring it to my mechanic who scans the car and it's giving him engine misfire...damnit. He suggests maybe changing the sparkplugs, doubtfull it was going to fix the problem I went with it regardless since they needed to be changed anyways. We swapped them out and one of them looked pretty bad...hey maybe it is the problem...wrong. The car drove the exact same only no misfire anymore. All he's getting now on the scanner is "undocumented code". This guy used to be a Nissan dealer mech. who started his own shop so he's usually very knowledgeable and doesn't miss a beat. Even he was dumbfounded and suggested I bring it to the dealer.

Anyways, I'd like to hear what people's opinions are before I bring it to the dealer and take it up the a$$. Any help would be greatly appreciated. Thanks guys.

Kehops

Oh yeah, and I drive a 1997 SE. So I'm guessing bad coils are not an option right? What symptoms do you usually get associated with bad coils? Thhanks gain.

njmodi

iTrader: (4)

1. Pull the codes, if the CEL is set, there should be something stored other than 0505.
2. Sounds like failing coils to me.

Kehops

I was under the impression that 1997 Maximas didn't have coil issues?

njmodi

iTrader: (4)

They don't have coil issues right out of the factory, but coils can fail on any car.. including the 97s... they typically fail under load - which is what you are experiencing.

njmaxseltd

iTrader: (19)

If your buddy is a true mechanic he should have been able to tell you whats going on by looking at the one "bad" plug you pulled out. The problem is definately on that cylinder. If the plug was black with soot, it could indicate a weak coil. If it was very light or yellowish, that would point to a lean condition most likely caused by a bad fuel injector.

Look at that spark plug better, it's holding the answer to your problem.

njmodi

iTrader: (4)

to what njmaxseltd said ... I missed the part of only one plug looking bad... btw, what plugs did you use for the replacement?

Kehops

NGK Platinums

Kehops

The sparkplug was on the blackish side. When we swapped them out and re-scanned the car, it wasn't throwing misfire anymore, just "undocumented code". He did mention a bad coil being a possibility but he had never encountered a 97 with coil issues, and I remembered reading somewhere that 97s usually didn't have failing coils. Maybe a bit of denial on my part too...

killcrap

iTrader: (3)

also check the Crank sensor REF. it could be the culprit.

Kehops

under decent/agressive load it doesn't jerk, only under WOT or normal load will it jerk. If that makes any sense.

How long can you drive on a bad coil? Can it have any other detrimental affects on the car?

Kehops

hmmm....funny you mention that because I just had the crank sensor replaced the week before this problem started. I had my clutch changed and the car wouldn't start anymore afterwards, mech. said it might be crank sensor but he couldn't be 100% sure so I went for it anyways and it started like new. Does crank sensor throw a code? Also, sorry if this is a stupid question but what does REF stand for?

Anyone else think this could be a viable possibility?

PAREDLINE

Lower RPM misfire can also be EGR. EGR activates at something around 1200 to 3000 RPM. Also look into your clutch. How old is it? Might be time for a replacement. The sputtering you feel might be the clutch losing grip and gaining grip or the friction material chattering on the flywheel- which may be warped as well.

Kehops

The clutch was 1 week old when this problem started

PAREDLINE

do you know if they resurfaced your flywheel?

Kehops

yes they did

PAREDLINE

Check your EGR metal tube. Make sure it on correctly. Do this with a cool motor because you will burn your hand.

I think the flywheel was not resurfaced correctly- it may be warped or machined unevenly. I've had this happen before and after they changed the clutch 3 times they realized the flywheel was warped.

Also check the crankshaft POS sensor. There are two sensors POS and REF. REF is under the crankshaft pulley and the POS is on the other side by the flywheel. the sensor might be loose or broken. I may have POS and REF mixed up. Anyway its the crank sensor by the flywheel.

Haynes manual has a process where you can check this sensor's resistance with a multimeter.

Kehops

Seems to me if the flywheel is warped, I would get this problem throughout the entire powerband no? And for the 1st week or so after it was fine.

Also something that could be of importance, when in neutral, I can rev it no problem and it doesn't hesitate, only when in gear and moving will it do it. Does a faulty coil also act up while in neutral?

Kehops

Does anyone know if a faulty ignition coil would act up while revving in neutral?

THEJEFFERATOR

does it "load up" or smoke black while it sputters?

njmaxseltd

iTrader: (19)

A weak spark caused by a failing coil is first felt via a misfire under a load. (heavy accelleration and especially at WOT) The spark plug being covered in black soot is definately a sign that it's not burning hot enough.

Another cause for a plug to be dark in color would be a leaking fuel injector. The misfire from a leaking fuel injector would be felt mostly at idle, not WOT.

I'm pretty sure you have a bad coil pack.

EGR problems and cam or crank sensors would not be cylinder specific.

THEJEFFERATOR

would a failing coil pack or injector set a code? my 95 is actin the same way, but stalls at idle and loads up, smokes black, gotta clear it out and rev it a few times. goes away for a while but comes back. sometimes un-driveable !!

MDeezy

iTrader: (27)

in the back of they haynes manual it shows various pictures of a spark plug and the result of various conditions. Match up your spark to the chart should help solve the problem.