I have a 1999 Maxima with 220,000+ miles on it. For the past six months the idle has been getting rough while in drive, last week it got really bad but keeps running. It's about 50% that under acceleration that there is a loss of power. No matter where the pedal is it feels like it's only 1/4 throttle, it's smooth while driving, just the idle is rough. I'm guessing coil packs, because I stopped by autozone so they could pull the codes and there were none.

 

If you're on the original coils then yes, replacing all 6 is where I'd start.

Just because there are no codes doesn't mean it points to any one specific problem.

 

My bud had an issue with his MAF sensor on his Altima and this sounds like the same symptoms. He cleaned out the throttle body and it ran much better. I am not ruling out the coils, but I would check this out as well. Another thing may be a dirty throttle body or egr tube. There is a thread on cleaning these item already.

http://forums.maxima.org/4th-generat...g-dummies.html

 

noob question, where's a good place to get coils? Better online or at a B&M in town?

 

I second the comment about cleaning the MAF and TB first. I didn't like the way mine was idling in gear (vibration at 500 rpm). I cleaned both and not only is it smoother, the idle rpm is about 100 rpm higher.

 

higher RPM is not any healthier by any mean

 

When i say rough idle, it's surging, cuting in and out. Its really bad right now. A scanner would makes things so much easier at this point. I thought i saw where DAVEB was selling them but he hasn't replied to my messages. I'm leary of getting them from ebay, and I really don't want to know how much the dealer is charging.

The whole intake system got a cleaning last summer when the egr valve went bad. The tube was pluged so bad i just bought a new one.

 

Vibration, low oil pressure, low voltage, and hell maybe even poor coolant circulation are not healthy by any means.

Anyways back to OP, I would suspect coil-packs since it's a '99. Pull a coilpack out and see if it says Hanshin anywhere on it or if it has a little mitsubishi logo instead, if it has the mitsubishi logo they are trash and you should replace all 6. If not I'd suspect the maf or plugs.

 

Try unpluging each coil plug 1 @ a time during idle & listen for a difference
This helps narrow down which bank/ clyinder/ cop/ inj, is giving you problems.If there is a "noticeable difference during this test feel free to change your fuel filter.

I would start with the fuel filter because it can cause your complaints & is the least expensive part to replace @ this moment

 

^
when you disconnect a coil if the engine starts to bog down and rumble that most likely means that coil is functioning. if you unplug the coil and nothing happens that is probably your defective one. atleast thats what i thought.

 

Correct that is what I tried to explain. Im sorry if I was not clear. "If there is a noticeable difference" This indicates the ign coil, inj, & spark plug is firing for that specific cylinder.