MrEous

iTrader: (11)

Mmmkay.

Starting last Saturday during a 'Twisties Roads Around Dallas' Tsunami benefit drive I noticed my car hesitated sometimes under WOT. The drive was around 100 miles from home. Yes, the drive was somewhat adventurous.

We finish off the drive and I notice my car is idling a little more rough than usual. During the next few days it still idles rough and I finally get a CEL.

Today I check it...0603...yay.

Yes, I know this means misfire on Cyl 6. Yes, I have read over the sticky and note it is either fuel or spark related. My friend had an extra coil from a '95 so I replaced my #6 with it. Still the same problem.

I drive home and notice that when I let off the gas the car tries to die. This happens repeatedly. It died once on the way home but otherwise everything else is the same. I also notice there is a fuel smell while waiting at lights...at the same time idle is bouncing 400-500rpms. I have a vid of that but it doesn't get any more fun than watching it bounce and hearing my exhaust sound like a Camaro with cams.

I get home...pop the hood and also reset the ecu. Getting 0505 now...thanks Nissan, glad to know my car is alright. Whatever, it still has the same problems.

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Things I have done in the last hour:
-Cleaned the tb = Clean
-Listened to each of the front injectors (stethoscope) to check for irregularity. (figured it was left bank related due to 0603 code) = All ok
-Checked MAF for anything out of the ordinary...you know, dirt, small animals, everyday things = All ok
-Reset ecu...to settle my OCD urges. ...Still 0505

Does anyone have any suggestions? Keep in mind I replaced the #6 coil already. The smell of gas worries me somewhat and makes me think it is more related to a spark problem.

I'm using copper NGKs right now and I believe they have around 20k-25k on them. I have some replacements I already bought this weekend figuring old plugs may be the culprit.

Of course...any info is greatly appreciated. Car has run fine up to this point aside from Cyl 5 coil going out at 35k.

MrEous

iTrader: (11)

...also wondered if someone thinks my EGR valve could be stuck open and not throw a code...?


(bump)

killcrap

iTrader: (3)

ohm out your TPS, and compare it to specs. you may also need to change your fuel filter if you havent dont it yet, nows a good time.

By monitoring the output voltage from the TPS, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A Broken or loose TPS can cause intermintten burst of fuel from the injector and an unstable idle because the PCM thinks thr throttle is moving

rejex

I have the same problem, my mechanic replaced all the plugs, put in a new fuel filter, and tested the tps (it is ok). .....I still have the rough idling problem..

love to hear how you solve this one~!

MrEous

iTrader: (11)

Thanks killcrap...I'll have my friend bring his multimeter today and we'll check the TPS. Before I call him over I'll go ahead and change the plugs...maybe the excessive driving last weekend killed them prematurely.

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Just curious but have you ruled out coil packs? Have you tested your injectors? Are you getting any cels?

konak85

iTrader: (10)

Try Checking the other coil packs.

MrEous

iTrader: (11)

Will ohm all coil packs as well...anyone else?

MrEous

iTrader: (11)

Damn...where are all the knowledgeable people today...lol

I think I might have found a problem. I was taking the engine cover from the front when I glanced at the intake manifold.

It looks like the upper/lower intake manifold gasket is 'sucked in' a little on the Cyl 6 side. The rest of the gasket sits flush with the manifold all the way around except for that section.

I am pretty sure this would cause the engine to overcompensate the extra air in Cyl 6 by dumping more fuel...causing a misfire.

We'll see in an hour or 2...I have a friend coming over with the necessary tools to help me out and also change the gasket.

adithius

Okay check the following:

Vacuum leaks
Leaking EGR valve
air filter clogged
fuel pump not delivering enough fuel to the fuel injectors
leaking head gasket
timing chain and/or sprockets worn
camshafts lobes worn

MrEous

iTrader: (11)

...Reading from the Hayne's manual? Yeah, me too. I think I found the problem though.

MrEous

iTrader: (11)

Pics of what the problem was...maybe it'll help someone else on here.

Notice the edges of Cyl 1, 2, 5 & 6?


Close-up of 1&2


Close-up of 5&6


Anyone know what might have caused this? Only thing I could think of is it was installed incorrectly and eventually a vacuum effect caused it to disfigure.

Thanks for everyone's help.