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-   -   Diagnosing Misfires on 2005 2.5L Altima (https://x.nissanhelp.com/forums/altima/20256-diagnosing-misfires-2005-2-5l-altima.html)

cb8100 10-14-2011 01:13 PM

Diagnosing Misfires on 2005 2.5L Altima
 
Hi, Everyone --

These forums have been a great resource for helping diagnose several problems with my 2005 Altima 2.5SL, but I'm absolutely stumped now.

The car has about 175k miles on it.

Long story inbound:

I've been having some problems on and off with misfires since May. First, the spark plugs went out. I replaced all the plugs and everything was fine for a couple of days. The check engine light came on and indicated the camshaft and crankshaft position sensors needed replacing. While I was waiting for the parts to come in, the car started misfiring on cylinders 3 and 4. I'd assumed this had to do with the CPS', so I waited for the sensors to come in, replaced them and the problem persisted. Next, I changed the coils. I ordered the coils from Amazon ($5 overnight shipping with Prime or wait 3 days for O'Reilly and Autozone to get stock). I swapped all the coils and everything was fine for another couple of days, then I started getting misfires on cylinder 4. I move the coil from 4 to 3 and the code follows the coil. I replace the coil (sent the old one back to Amazon) and everything's fine.

A couple of weeks later, another one of the Amazon coils craps out. A replacement and everything's fine for a month or so.

Since July, I've had days where I'll get misfires (usually humid days and on a warm start) for a couple of minutes and everything's fine.

This past Wednesday, the car was misfiring from a cold start. I hobble home and there's smoke coming from the hood. I pop the hood and there's oil coming out of the valve cover and hitting the manifold.

Today, I replaced the valve cover gasket and found oil on spark plugs two and three. After cleaning all the gunk off the engine block and valve cover, I replaced the gasket, cleaned the plugs and went for a test drive around the city. After about 10 minutes, I started getting misfires on two again. Given the oil I found on the two plugs, I stopped at O'Reilly and got four new plugs and swapped them all out. There was no oil on any of the plugs when I pulled them out this time.

Everything was fine for about half an hour, but now I'm getting misfires on cylinder 2 but only when idling or under 40mph. I'm going to start moving coils around again to see if the code follows the coil, but I started thinking about the fuel filter (yes, I know, I have to replace the entire pump).

Is it logical that the fuel pump/filter could be causing misfires? I'm really hoping it's just another coil from the Amazon batch that's crapped out, but I'm starting to think about backup plans. Also, is there anything else I should consider if it's not the coil (and obviously not the plugs)?

ETA: No oil coming out from the valve cover gasket, so at least I got something done right.

NissanTech 10-14-2011 09:45 PM

Quote:

Is it logical that the fuel pump/filter could be causing misfires?
No usually a bad fuel pump will not give you that symptom. Before replacing the coil, or if the coil is already bad, after replacing the coil add a grounding kit to the engine. I have seen problem when a bad grounds will cause the coils to go bad, also some owners claim that the grounding kit will also improve performance.

cb8100 10-15-2011 01:45 PM

So, I got over my laziness and frustration and swapped coils 2 and 3, erased the codes and drove to Autozone. The car started misfiring half way there. I check the codes in the parking lot and the misfires had moved from 2 to 3. I bought the last coil in stock, swapped it out in the parking lot and erased the codes. All appears well.

Oh, and it was the last coil from the batch I bought from Amazon. What kills me is that the coils I got from Amazon were Becks Arnley, who OEMs the coils for Nissan.

I'm going to check the grounds on Monday. My multimeter walked away on me, but I have one at work I can borrow.

bennyb53 10-15-2011 03:01 PM

On my 02 Altima 5 Spd., 96k miles.

OEM Parts: Ignition Coil - Hanjin (3 still OE), O2 Sensors - NGK/NTK, Spark Plugs - NGK - PLFR5A-11, Drive Belt - Bando. But I'm using Gates. Motor Oil - Castrol Full Synthetic 10w-30, Transmission Fluid - Redline MT90. Disc Pads - Akebono but I'm using aftermarket ceramic. Genuine Nissan crankshaft, camshaft, and immobilizer unit.
Standard Motors - PCV from NAPA. As always, consult your owner's/service manual for Specs and proper oil grades.

When buying aftermarket critical parts, look for key words or phrases such as; Direct OEM Replacement, Inter-Motor Exchange, list the actual Nissan part # being replaced. Remember OEMs also sells aftermarket. Do your research Online before even going to your local parts store. And establish a good working relationship with 1 or 2 sales staff who you think is knowledgeable.

Most of all, if you think you're due for replacement, go ahead and do it so you have time to shop for parts online or your local auto parts store. You'll save a lot of money than waiting for the MIL or breakdown away from home.

zapo04 12-03-2011 10:38 AM

having similar problems to cb8100. My crank and cam position sensors gave away. Replaced. Then 3 months later started getting P0303 code. Swaped coil 3 with coil 2. Problem followed got P302 code. Replaced bad coil and all spark plugs. Ran for about 50 miles now getting a P0303 code again. Any help would be greatly appreciated. thanks in adavance.

streamcast 12-04-2011 03:18 PM

Agree with Nissan Tech. Check and or replace grounds.

zapo04 12-05-2011 04:13 PM

P0303 issue
 
which grounds? Can you please specify? thanks


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