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P0302 & Jumpy/shuddering

Chrysler 200 2012 3.5L
P0302 engine light code

Replaced spark plugs - still get the light.
Swapped ignition packs - still get the same code.
Put fuel injector cleaner in and working through the gas currently.

Car also “shudders” or feels jumpy while rolling forward in “Drive” (automatic). Is this caused by the misfire? Any suggestions for a plan of attack for repair ?



Yes, a misfire can make the car jumpy. Maybe do an injector swap as well. A bad injector can cause a misfire.

You should do a compression test on the engine. If #2 is low, you may have an internal mechanical problem causing the misfire. Piston rings, bad valve seal or even head gasket.


I’m always a proponent of making sure the engine is sound mechanically for the simple reason that over the years I’ve seen so many cars that have had everything in the parts inventory thrown at them without curing the problem. So a compression test is always mandatory with a performance problem.

If you want to make things a bit easier before a compression test I might suggest the use of a vacuum gauge. Those can be connected in seconds and will tell you instantly whether or not to proceed with a compression test.
The vacuum gauge (they’re cheap from Harbor Freight or whatever; not so cheap from Snap-On) is connected to an intake manifold vacuum source and the engine allowed to idle. An engine with good compression will usually show around 20" of vacuum with a rock steady gauge needle.


Thank you very much. I will get back to you on outcomes!

Thank you, I will try these methods as well if a simple injector swap doesn’t solve the issue for me.