My 2011 Dodge Grand Caravan has a random misfire, I have replaced the vacuum lines, ignition coils, spark plugs and fuel pump oil change and air filter and it still misfires! Does anybody know what could possibly cause this? The only codes on the van are P0300 random misfire!!

It is very prominent at idle and goes away mostly when driving, it’s only when the engine warms up to operating temperature. I can’t find out what it is!! Thanks in advance for any answers.

 

If the engine is a 3.6L it could be rockers or camshafts. Do you hear what sounds like lifter sounds?

 

It doesn’t appear to be lifters or rockers, I took off the valve covers and checked if it was within spec for the manual and it was, checked compression and fuel pressure and that was all within range. Past that I don’t know what else it could be except perhaps fuel injectors? But they all seem to fire when I took them off and applied a small voltage.

 

It could be a bad cylinder head early on this was problem with 3.6 L Pentastar engine it usually it the left head Chrysler has an extend the warranty on this cylinder head to 10 years 150.000 miles on 2011, 2012 and 2013 Grand Caravan models. Get a compression test done if the heads is bad then proceed with checking with a dealer if you're covered under warranty,

 

Thank you, I just replaced the number 6 fuel injector as well, still misfires, compression test coming soon, is it the head itself or the head gasket? The van has 158k miles on it, if it is just the gasket I will do it myself, if it is the head does it require replacement to fix the issue or can I have the head itself resurfaced?

 

Just did an 02 sensor voltage reading, at operating tempt both sensor 1 bank 1 and sensor 1 bank 3 were jumpy and reading between .055v and .75v at times, the jumps down to .055v only happened every 10 seconds or so. Sensor 2 on bank 1 and 3 stayed fairly steady with only .1v of deviation at operating temp, staying at .9v or so. Could this cause that issue? If so why both at the same time?

 

We are doing a resonator delete and muffler replacement to stop any blockage

 

Put on a cherry bomb muffler, replaced MAP sensor, isn’t fixed yet, compression on all cylinders is 115psi, oil pressure is good, still don’t know what it could be, anybody have any thoughts?

 

i having same issues. What was it?

 

Have done most of the same tests as the original poster and replaced my pcv valve, battery, and alternator with no luck. Either of you two get any solutions?