2004 Chrysler Pacifica, P0304 Misfire Cylinder#4
 

I have a 2004 Chrysler Pacifica 3.5L
and I have a have a P0304 Misfire Cylinder#4 Detected
I did a tune up and I replaced the Fuel Injector on Cylinder#4 with a
OEM Fuel Injector from the Dealer. and I cleared the codes.
But P0304 came back again:confused:

Can someone help me????

Is this the only code? Another strong possibility is that the intake gasket has split and slid down. About the only way to see it is to take the plenum off and look down the ports, you may even have to take the intake off. Do you know how to check for a vacuum leak?

Yes P0304 is the only code, I have in my car unfortunately.

Do you mean the Intake Plenum Gasket? Or the Intake Manifold Gasket?

I dont know how to check for leaks, is it easy?

Have you encountered this P0304 on these Chrysler Pacificas?
Ive noticed some threads in this Forum, many people have
the same P0304 just like me

The lower intake is the one that has the gaskets that sometimes split from deterioration and slide out some making a vacuum leak. If the upper part is off, you can see down in there. I use something I can spray down in the sealing area (while it's running) that is NOT flammable. Some people use NON-Flammable brake parts cleaner. I use that and rust penetrant..whatever is handy to me at the time. When you hit the sweet spot, you'll notice a change in the idle.

Before you get too much more radical with repairs, try and get a compression test done. Or rent a guage set and do it yourself.

I'm sorry, I can't be of much help to you regarding a misfire, but I can tell you that a P0300 (Random/Multiple Misfire Detected) and the starting troubles drove me crazy enough to replace the entire engine.

Wow, I definitely feel for you. BTW how many miles were on engine before you had to replace it? Was there any other problems like engine using oil before the misfire problem started?

Thanks your sharing your experience.

At the time of replacement, the engine had approximately 106,000 miles. The engine was as sweet as a nut while running, but was a pain in the (insert body part here) to get started again. Sometimes up to 15 minutes of hard pedal-pumping and cranking. One day it legitimately took us a total of almost an hour of cranking (not all at once) to just barely get it started. At that point, we bought and installed an identical engine with roughly 55,000 miles on it. I will admit that with the old engine the coolant was regularly murky & oily and there was always a sweet smell to the exhaust (rich a/f mix? cylinder head gasket?) and when starting, it would miss and sort of stumble over itself when starting, but once started, ran beautifully... The new engine has a worse oil consumption rate than the old one, but there's no smoke coming from the exhaust or drops in my parking spot... Either way the old engine had a nice thick layer of carbon deposits all over the engine from the previous owner (We ONLY use Mobil 1 Full Synthetic in all our cars).

Drop the synthetic, I bet your oil consumption goes down.

I'd say; drop the Chrysler and much more than just oil consumption will go away. ;)

Just couldn't resist, lol.

lol to be honest, since posting that, oil consumption has decreased significantly. I have no idea why, but it appears the engine likes to consume more oil if you keep changing oil brands or types (or am I totally wrong here?)