Misses at low rpm

Hi,

If the plugs are original, I would replace them. Have you scanned the computer to see if there is a diagnostic trouble codes specific to which cylinder is causing the misfire? That should be done. Here is a quick video showing how it's done:

https://youtu.be/Cg1WO0UKIYM

Here is a list of OBD2 codes you can reference when you get the codes.

https://www.2carpros.com/trouble_codes/obd2

I realize most people don't own a scan tool. However, most parts stores will do it free of charge. This is where I would start.

Now, you listed this as a 3.5L 4 cylinder. That isn't correct. It is either a 3.5L V6 or a 2.5L 4 cylinder. I need to know which one you have.

Let me know if you are able to have the computer scanned and which engine you have.

Take care,
Joe

Thanks for getting back. the way the problem started when symptoms felt like a plug fouled (head gasket). head good. code po302 cylinder two misfire.. should I replace four plugs/four coils set? $115.00 or could I get away with plugs only?

Joe..it's a 4 banger thing 6 speed, stick.2.3.

Joe.. sorry..I'm no mech..engine..2.5 ..170hp.

Hi,

No problem. If the coil is good, you can just replace all the plugs. If you feel the coil could be the issue, then switch that coil with a different one and see if the misfire changes cylinders.

Here is a link that reviews and explains how to do a tune up:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Here are the directions specific to your vehicle for spark plug replacement:

2007 Nissan-Datsun Altima L4-2.5L (QR25DE)
Removal and Replacement
Vehicle Powertrain Management Ignition System Spark Plug Service and Repair Removal and Replacement
REMOVAL AND REPLACEMENT
SPARK PLUG

Removal and Installation

Exploded View EM-14
pic 1


REMOVAL
1. Remove the ignition coil.


pic 2


2. Remove the spark plug with a suitable spark plug wrench.

INSPECTION AFTER REMOVAL


pic 3


^ Do not use a wire brush for cleaning the spark plugs. Replace as necessary.
^ If plug is covered with carbon, a spark plug cleaner may be used.
Cleaner air pressure: less than 588 kPa (6 kg/cm2, 85 psi)
Cleaning time: less than 20 seconds


pic 4


^ Checking and adjusting plug gap is not required between change intervals. If the gap is out of specification, replace the spark plug.
Gap (nominal): 1.1 mm (0.043 in)

INSTALLATION
Installation is in the reverse order of removal.


pic 5


_____________________________

Let me know if you have questions and if this helps.

Take care,
Joe

Joe thank..I changed all plugs... for 200k. They were beautiful...the coils all looked perfect.. .#2 coil has burn mark at the boot only coil that I can afford ...am I on the right track?I couldn't find anything.else...can I replace just one

I didn't have access to a scan tool today, so I didn't switch coil.

No problem. I would recommend getting the spark plugs replaced. You got your money's worth from them. LOL

If the misfire continues, then switch the coil from cylinder 2 to a different one. Run the vehicle and see if the misfire changes cylinder. If it does, then you know it is the coil.

As far as codes related to a misfire, it's simple. You have a P0302 which indicates a cylinder 2 misfire. A P0301 is cylinder 1, a P0303 is cylinder 3, and P0304 is cylinder 4.

If you switch the coil from cylinder 2 to cylinder 1 and find a P0301, then you know the misfire has moved cylinders and the coil is bad.

Let me know what you find or if you have questions. Also, plan to replace all the plugs.

Take care,
Joe

I bought a coil 2dY. car runs great thanks.

Excellent. Glad to hear you got it taken care of. Please feel free to come back anytime you have questions in the future.

Take good care of yourself,
Joe