Engine runs sluggish, cylinder 4 misfire code

[csprinkle]

Hey all,

 

Just scanned my 2002 Nissan pathfinder LE since the check engine light has been on/blinking for quite some time now. I posted previously about this but I gave little detail, so this time I come bearing codes. The codes are 'P0304 Cylinder 4 Misfire Detected' and 'P0740 A/T TCC Solenoid Circuit Malfunction'. I am by no means a car guy so I don't know what these mean, so I came here for assistance. I probably have tools to repair most things but I'm on the edge about buying parts for repairs because I could use that money to save for a new car instead (I don't know if I will bring my pathfinder to college). But if the parts aren't too pricey I'll try and fix the car up. So far, I've received suggestions that I should swap cylinders from another to #4, replace spark plugs (although my dad replaced plugs fairly recently), and even to use a compression tester (?). So, would a beginner be able to tackle these repairs (P0304 & P0740) or should I take it into the shop instead?

 

Extra unnecessary info: It might be worth noting that my dad owned the car for about 20 years so he knows some repairs but not the specific codes that came up. I've done research on the codes in the forums here and saw that there could be a pressure leak in one of the cylinders (?). Images of the scans are attached (in case you can't see them, the only additional info are parts that the scan recommended I buy for the repair).

 

 

Thanks,

Cameron Sprinkle

Edited July 8, 2023 by csprinkle
forgot to add in past repair suggestions

[Slartibartfast]

The misfire is worth sorting out sooner rather than later. If it's an ignition problem, it's throwing unburned fuel into the catalytic converter, which isn't great. If the coil pack is accessible, I would try swapping it for one from a cylinder that isn't misfiring. If the miss follows the coil, it's the coil. If #4 continues to misfire with a known good coil, pull the #4 plug, see if it's obviously fouled or damaged. If it's not a spark issue, might be compression or fuel. I haven't messed with VQs enough to know how much of a PITA their coil packs are to get to.

 

The torque converter clutch circuit might be a little more complicated for a beginner. I would look for any obviously loose or corroded transmission wiring underneath.

 

There should be troubleshooting for both codes in the service manual, which you can download for free here. AT section for the converter clutch code, EC section for the misfire. Might help decide whether it's something you're comfortable with doing. The later manuals show a lot of hand-holding for a scanner you don't have, but they still included some useful information here and there.