P0302 on Dodge

The electronic throttle body fails from carbon buildup and TPS sensor malfunction. Causes rough idle, stalling, hesitation, and check engine light. Common across all 2.4L World Engine applications.

Some 2015-2021 Dodge Challenger 5.7L and 6.4L engines can develop a persistent engine-speed-related tick, rough idle, loss of power, or misfire from hydraulic roller-lifter, roller, or cam-lobe wear. A tick alone does not prove internal wear: exhaust-manifold leakage, injector noise, oil-pressure concerns, and other causes must be ruled out. MDS fitment is transmission-specific, not engine-name-wide: automatic 5.7L and 6.4L applications use cylinder deactivation, while six-speed manual applications are non-MDS. Cam and lifter wear is not limited to MDS hardware.

The 3.6L Pentastar V6 engine can develop a ticking noise from worn rocker arms. Unlike the HEMI MDS tick, this is caused by the roller follower rocker arms wearing out prematurely. The issue typically appears between 50,000-100,000 miles and is more common on 2011-2013 engines but can occur on later models.

The production valve springs on the 6.4L 392 HEMI can crack or fracture. A weakened spring can cause a persistent single-cylinder misfire that remains after plug, coil, or injector swaps; a complete fracture can let the valve contact the piston and cause major cylinder-head or engine damage. High-RPM and modified/cammed use changes valvetrain load, but the correct replacement spring must be selected from the camshaft's lift and required installed/open pressures rather than from boost alone.

A P0300 "random/multiple cylinder misfire" code with a rough, shaking idle is one of the most common drivability complaints on the Dodge Challenger, and on a high-mileage or maintenance-overdue car it is most often caused by worn spark plugs and/or weak ignition coils rather than an internal engine fault. The 5.7L and 6.4L HEMI V8s are especially prone because they run two spark plugs per cylinder (16 total), so worn plugs are a frequent misfire source; the 3.6L Pentastar V6 also commonly throws misfires from failing coil-on-plug units. Because P0300 is the "random/multiple" code (versus cylinder-specific P0301–P0308), it points to a condition affecting several cylinders at once — typically a full set of tired plugs, or coils that break down intermittently under load/heat. Owners notice it most at idle and during light acceleration. Critical: if the check engine light is FLASHING, the misfire is severe enough to dump raw fuel into the exhaust, which can quickly overheat and destroy the catalytic converter(s) — turning a routine tune-up into a far more expensive repair. Note: the 2011–2013 3.6L V6 also had a documented left-cylinder-head defect (Chrysler warranty extension X56), and 2014+ Pentastars can suffer rocker-arm needle-bearing wear; these can present similar misfire codes and should be ruled out if new plugs and coils don't resolve the P0300.

HEMI engines with Multi-Displacement System (MDS) can develop a ticking noise from the MDS lifters. This tick is most noticeable at idle and during light acceleration. While often not causing immediate damage, it can indicate lifter wear that may eventually require attention.

The 3.6L Pentastar V6 can develop a ticking noise often related to the rocker arms or hydraulic lifters. This is common on engines with higher mileage or irregular oil change intervals. Some early Pentastar engines had rocker arm design issues that were later updated.

HEMI engines with Multi-Displacement System (MDS) can develop a ticking noise from the MDS lifters. This is most noticeable at idle and during light acceleration. While often not immediately harmful, it can indicate lifter wear.

The 3.3L and 3.8L V6 engines suffer from water pump failures, thermostat sticking, and radiator fan relay failures. Overheating can cause head gasket failure. Fan relay is the most common single failure point. Same cooling system as Chrysler Town & Country.

Debris accumulates in cylinder head coolant port at primary thermostat housing, blocking coolant flow and causing overheating. Typically occurs around 78,000 miles. Can cause head gasket failure or engine damage if not addressed.

2014 models with 2.4L engine notorious for head gasket failures around 100,000 miles. Fails due to overheating issues and possible manufacturing defects in gasket material or cylinder head warping. Plastic thermostat housing contributes to overheating.

Early 3.6L Pentastar V6 engines suffer a left-bank cylinder head defect (valve guides/seats) that causes loss of compression and misfires on cylinders 2, 4, or 6. The problem was widespread enough that Chrysler issued TSB 09-002-14 and extended the left cylinder head warranty to 10 years/150,000 miles under campaign X56.

The single most documented first-generation Neon failure. The original-design head gasket weeps and then fails, most commonly at the driver's-side rear of the block where an oil passage crosses close to the block's outer edge, near the brake-fluid reservoir. Because the SOHC and DOHC share the same block, both are affected; R/T and ACR (DOHC 150 hp) cars are equally susceptible. Failures frequently appear at 40,000-70,000 miles and are aggravated by the engine's marginal cooling and the early torque-to-yield head bolts. Chrysler acknowledged it with TSB 09-05-98 (later superseded by TSB 09-08-99), releasing a redesigned multi-layer-steel (MLS) head gasket that also carried over to related 2.0L applications.

Composite head gasket design inadequate for V10 heat output. Gen 2 (1996+) upgraded to MLS gasket which resolved the issue. Gen 1 owners should upgrade to MLS design during any head work.

Oil starvation during sustained high-speed cornering causes rod bearing failure and catastrophic engine damage. Oil surges away from pickup during hard lateral loading. Gen 3 (2003-2006) more prone than Gen 4 (2008-2010). Primary risk during track use.