jgilbs

So my '03 has a pretty rough idle, but throws no codes and has no driveability issues. It also seems to be missing. I am thinking it is a bad coil or plugs/wires. How do I diagnose a bad coil? I dont want to spend $300 to replace all the coils on a hunch.

MichMaxFan

I will try to help, but here goes...

When I had a coil prob in my 2000, it tripped a code. That helped. However, if you are pretty certain it is a coil, it will (at least my case) run rough at ALL times. I don't know how a coil could not act up only while idling.

Anyway, if you go the coil route, my suggestion is to buy 2 coils, one of each style. The 3 coils in rear are one type, 3 coils in front are another. Then, you swap just one coil at a time and record findings. This may take a while, but it is cheaper than buying all 6, and you'll then have a spare, too. It worked for me, but it was time consuming.

Call dave at the nissan dealer mentioned a billion times on here.

bullet187

Does the rough idle occur also when in park? Get worse with the a/c on? Check the gap on your spark plugs to make sure they are in spec. I doubt your coils would be bad without throwing a code.

jgilbs

Cool, thanks for the info guys. A little background, my max is an 03 with 157,000 miles on it. It's very possible the plugs are bad. Would re-gapping them be worth it, or should I just replace? (I got the car used and have no idea when/if ever they were done)

It is rough in D, but smooths out in neutral....yes it seems to get worse with the AC on.

MichMaxFan

If it were me, now that's me talking, I'd replace them since you have no idea of age/miles on them.

Put in good quality. Not cheap.

Xpcgamer

iTrader: (5)

My Max does the same thing. I feel it rumbling a bit when at a light. Mine is a 6 speed thou. I also have a slight stumble b/w 2 and 3k rpm. I have replaced the MAF sensor and did the ECU pedal dance but it is still there. I think its safe to say that the coils would be more constant of a problem. Try the plugs and reply back to see if that took care of the problem. I will do the same once I get my car back from the body shop.

norcallump

iTrader: (1)

like Xpcgamer, I have same issue with a 6spd, from 2-3k. I have new coils, but when motor was replaced, mechanic said plugs looked good, and dropped them back in. Guess I might as well replace them

mandyfig

How about cleaning TB?

jgilbs

I am buying new plugs, wires tonight. TB cleaning sounds like a good idea as well. After I do that, do I need to redo the idle intake procedure?

Thanks for all the replies guys.

PS - Is anyone else having issues with their post count being way off?

jgilbs

Do I need the gasket to install plugs? Or is that just for coils?

bullet187

You don't need gaskets for plugs or coils. If you get new plugs make sure to check the gap. Last time I got new plugs the gaps were all off.

MONTE 01&97 SE

iTrader: (1)

You wont be buying wires as we dont have them...hehe. You dont have to do the idle procedure, but why not.

jgilbs

So I went out to the car to check codes, and although I had no stored or thrown codes, I did notice 2 things
1)I heard a sucking sound that almost sounded like a vacuum leak right near where the brake booster vacuum hose attaches to the engine. Could this be the air in the manifold itself I am hearing? Or should I replace the brake booster hose?
2)I noticed the gaskets on the upper collector were crooked - ie, the tabs where the bolts are supposed to go were sticking up where there are not any bolts. Whoever put them on clearly didnt know what they were doing. Should i replace these? What are they called if I goto NAPA?

bullet187

[quote=jgilbs;8092077]So I went out to the car to check codes, and although I had no stored or thrown codes, I did notice 2 things
1)I heard a sucking sound that almost sounded like a vacuum leak right near where the brake booster vacuum hose attaches to the engine. Could this be the air in the manifold itself I am hearing? Or should I replace the brake booster hose?
quote]

Spray TB cleaner where you think the leak is. If the RPM's go up then you found the leak, if nothing happens then you don't have a leak.

Xpcgamer

iTrader: (5)

I just read the procedure for replacing the plugs and you will need the mani gasket. I am not sure of cleaning the TB as I have read of all the issue's that may happen. Somebody did do something genius by leaving switch to "on", putting it in gear and flooring the accelerator which caused the plate to open. Once opened he wiped down the TB. I might go that route IF the plugs don't solve my issue.

jgilbs

Is the manifold gasket different from the other gaskets used within the manifold assembly? Like I said, the gasket that is screwed up is part of the manifold, not under it.

mandyfig

A clean TB helps a lot!

mandyfig

Which reminds me, I have not done it on my Max.

bullet187

Which gasket are you talking about? There is only one gasket for the manifold and it is under it.

jgilbs

Gasket I was referring to was the throttle body gasket. Put it back n, haven't noticed any issues.

I got NGK iridium plugs, and checked gap on them. I replaced all plugs, and I found the plug near the driver side on rear bank was loose, and was filled with oil. Ended up replacing the valve cover, as the spark plug tube gaskets are integral to the cover. Had to drive 50 miles to a dealer that had one in stock as I had to drive to our family reunion on Friday, 2 states away. Good news is, I cleaned the TB, new plugs and new valve cover, and now the car runs like a champ.

OnOiShNo0dl3Z

iTrader: (2)

Someone mentioned that you have different coils for the front and rear cylinders. This is Not the case for the 5.5 gen maxima (02-03).

Also, the suggestions on cleaning the Throttle Body, I'd be very careful if I were you. It's pretty much not recommended but if you must, do NOT manually move the butterfly valve.

This usually results in a high idle. In order to fix the idle, you would have to do a 'pedal dance' that requires pretty precise timing. If not, then be prepared to pay the stealership about a hundred bucks to press a few buttons on the consult II to fix it. If these don't fix it, you're looking at buying another throttle body.