Staff Answer
Oct 01, 2026 - 12:15 AM
On your 2020 Dodge Durango GT, if you've already replaced plugs, coils, injectors, and the PCV valve and still getting random misfire codes — the usual suspects are now exhausted, which points to something deeper. Here's where to focus:
Check for a vacuum leak first: a cracked intake boot, loose hose, or failing intake manifold gasket will cause random misfires across multiple cylinders and is commonly overlooked after replacing the obvious parts. Spray carburetor cleaner carefully around the intake manifold and vacuum lines while the engine idles (any RPM change indicates a leak).
Next, check fuel pressure: a weak fuel pump or clogged fuel filter not maintaining proper pressure under load will cause random misfires that no amount of ignition parts will fix. A fuel pressure test is quick and inexpensive.
Also pull your cam and crank position sensor codes carefully: on the 3.6L Pentastar engine in the Durango GT, a stretched or worn timing chain is a known issue and causes random misfires, rough idle, and cam/crank correlation codes. This is especially true if your misfires are worse on cold startup and settle somewhat when warm.
Finally, do a compression and leakdown test: if one or more cylinders are showing weakness, you're dealing with a mechanical issue no sensor or ignition part will solve. Given everything you've already replaced, this is absolutely worth ruling out.
Hope this helps!
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