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2004 RAM 5.7 Hemi Misfires: P2308 to P0302 Code Transition - Diagnosis & Fixes

Model: 2004 RAM Fault Code: P0302 Posted: 2015-10-21 10:37

I'm not a mechanic, but I'm sharing what I've observed and what my mechanic has done so far. A few weeks ago, my 2004 RAM started shuddering and misfiring, especially when accelerating uphill. The initial fault code was P2308 — indicating an ignition coil C secondary circuit issue. After replacing the ignition coil, the problem stopped for about 10 days. However, it returned a few days ago without any error codes. Today, I managed to reproduce the condition again and noticed a new code: P0302 — cylinder 2 misfire. The shudder is most noticeable when giving the truck gas on an incline, but not enough to cause downshifting. The engine shakes violently until it reaches the top of the hill or levels off. I'm wondering if this could be related to a faulty spark plug, ignition coil, or fuel delivery in cylinder 2. Since the P2308 code initially pointed to coil C, and now we have P0302 (cylinder 2), I suspect either a worn coil or a misfire originating from that specific cylinder. Any insights on how to diagnose this further? Should I consider swapping the ignition coil for cylinder 2 with another one to test? Also, my truck is equipped with a 5.7L Hemi engine.

Related fault codes
P0302P2308
Comments (6)
Anonymous 2015-10-21 11:03

Did your mechanic replace the spark plug in addition to the ignition coil? I noticed you had P2308 initially and now only see P0302 — was that code present during the earlier fix or did it appear after the replacement?

Anonymous 2015-10-21 13:21

The spark plugs were replaced long before I purchased the truck, likely several weeks to months ago. My mechanic only replaced the ignition coil this time when addressing the P2308 issue. Currently, only P0302 is showing — and it was cleared prior to testing, so P2308 is no longer present.

Anonymous 2015-10-21 18:32

Since your mechanic resolved the P2308 issue with a coil replacement, it's reasonable to have them address the current P0302 code. While P0302 is a broader misfire code, it specifically points to cylinder 2. A simple test — swapping the ignition coil for cylinder 2 with another known good one — could help confirm whether that’s the root cause.

Anonymous 2015-10-22 03:54

What type of engine does your 2004 RAM have? This might influence how misfires are diagnosed and what components to inspect.

Anonymous 2015-12-04 20:10

It has a 5.7L Hemi engine.

Anonymous 2015-12-04 20:13

I took it to the dealership, where they were planning to replace the spark plugs as a next step since they couldn't identify any other issues. Unfortunately, during a test drive today, they attempted a brake torque test and accidentally damaged the transmission — a serious setback. Their diagnosis seems flawed, and I’m now considering further DIY or independent diagnostics.