maxima_million

I'm not sure how to explain this, but I'll try. It started about 3 weeks ago. When I am at a red light/stop sign etc, every once in a while (and getting more frequent) I will feel as if the engine wants to engage and sometimes the RPM's may fluxuate. I have not done any work on the car recently but DID buy spark plugs. A buddy indicated it might be the fuel recycling being clogged but I'm not sure. I have always used super gas and change the oil every 3k. I have 158k miles.

Any suggestions would be appreciated!!

f550maranello2

iTrader: (2)

what about a tune up? what kind of spark plugs did you use?

You might wanna do some maintenance first.. aka clean tb, IACV (by removing all valves then adjusting the idle)

Also checking the vacuum hoses would be a good idea..

maxima_million

I did clean the TB and IACV a few months ago + I use OEM spark plugs. Never considered a vacuume hoses.... that's one possibility! Thanks

JNCoRacer

iTrader: (6)

Youre not getting lazy with that right foot and pressing on the accelerator and brake at the same time are you?

Have to ask. My ex wife did that a few times.

JNCoRacer

iTrader: (6)

Youre not getting lazy with that right foot and pressing on the accelerator and brake at the same time are you?

Have to ask. My ex wife did that a few times.

pmohr

iTrader: (26)

What do you mean as if the engine 'wants to engage'? Do you mean it's misfiring, or what?

Any codes?

maxima_million

LOL - No, I only drive with one foot! It's hard to explain.... regular driving is fine. It only happens when I'm stopped. It will idle fine then I feel a 'thud'. It happens for only a quick second. Could that be a mis-fire? It doesn't happen all the time, but then again, it happens more often each day....

pmohr

iTrader: (26)

What is 'thud'ing?

Again, codes?

And what year are you, since you neglected to fill out your profile, or tell us?

MeSSiaHd

I know this may sound dumb, but i have to ask if it's a manual or A/T? Because ive had that same problem only with a M/T. The problem then was the clutch lining. Now if its a A/T, i'll ask a couple of my friends.

Jake95maxxi

The car might not be getting enough fuel.. Mabe the fuel pump is screwed up.. Mine was.

maxima_million

My profile is updated (sorry - didn't know it was there). It's a 1998 Auto SC-A/T. I didn't consider the misfireing, but it sounds logical and I do have the replacements. I replaced the orig. spark plugs at 80k and I'm nearing 160k...

maxima_million

How did you know?

maxima_million

Codes: I do have an 02 code: 0509. I replaced the front 02 and the code continues ( I SHOULD have mentioned that)

DBear

Change your plugs. I had an occasional idle drop at stop lights too. My plugs only had about 15K on them, but they weren't NGKs. When I put in NGKs, the problem went away.

Edit: Not clear from your post whether it's an idle drop or a surge. If it's a surge, I wouldn't think it's the plugs.

modenaf1

iTrader: (3)

I would check out the plugs. Maybe a coil pack starting to go too.

What you are describing sounds a lot like a misfire to me. I would say it is most likely your plugs, maybe a coil pack, and it could possibly be a fuel issue too (clogged injector, low fuel pressure, etc.). Also, when was the last time your fuel filter was changed?

modenaf1

iTrader: (3)

True, I am with DBear on this one. From what you are describing sounds a lot like a misfire to me, but it could be a surge.

So, if your car is idling normally, what is the first abnormal event that occurs? Does it spudder? If so do the RPM's drop? Do they go up? Do they drop then do they go up?

EnervinE

iTrader: (11)

If it feels like a momentary "thud", and you see the RPMs drop by 50 or so, it's misfiring and you've probably got a coil on the way out.

mightyMax95

iTrader: (5)

you sure you changed the correct o2 sensor? if you're still getting a code for it, might have changed the wrong one (bank 1 is the firewall side). i made that newb mistake and was getting a misfire since the bad sensor was still there, pretty much the exact symptoms you described.

maxima_million

I am on my way to the store to get a spark plug socket and change all 6 plugs. Strangely, it did not occur once yesterday... The fuel filter was changed about 6-8k miles ago. I'm pretty good with that! I'll post with an update in a week or so! Thanks everyone for the feedback!

maxima_million

k, long story/short: I changed all sparkplugs and I ended up having a conversation with a Nissan Tech. I asked the same question and he thinks it's because I cleaned the IACV and did not reset 'the computer'. I reset the ECU, but he indicated it's something that only a tech can reset. He indicated he would do it no charge sooo....

BTW: same behavior: the RPM's dip then jump up... that's when I feel like the car begins to engage 1st gear or 'thud'.... I hope to make it to Nissan next weekend since I'm heading off to a honeymoon VERY soon!

Oh yea - he indicated he's seen 4th generation Maximas over 300k miles.... THAT really made my day!

JwaxMax99

iTrader: (14)

What "reset" is this , that a Nissan tech can only do?

maxima_million

It's not the odb2 computer. Essentially the computer had to be retrained to a clean reading. The rpms were adjusted higher allowing more air. Problem fixed