2004 Chrysler Pacifica Troubles! HELP!

I am lost! I’m hoping someone here can see what I haven’t.

I did an engine swap for my 2004 Chrysler Pacifica 3.5L V6 engine a few weeks ago and everything went great. I drove it for about 2 days and it drove fantastic. The engine had real power to it etc.

The old engine had 160K Miles on it. The new one I bought from a great company on eBay had 81K miles on it. The engine looked great and it is in an amazing shape. Here is what’s going on.

I was driving in the city after 2 or 3 days with the new engine and it started shaking pretty badly and I immediately pulled over to the side and shut it down. I had it towed to my driveway.

I used my OBDII scanner and I saw the P0172 code and the engine smelled like gas. Took the dip stick out and it also smelled like gas as well. No notice of milky pattern of a blown head gasket (This is not the case because the car doesn’t display the symptoms).

When I took the intake manifold out, it was full of gas near the throttle body and it was a lot of it. I cleaned it out and put everything back together and the engine started immediately. It flooded with gas again. I know that the code suggests the following possible causes:

  1. The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of “oiled” air filters can cause the MAF to become dirty if the filter is over-oiled.
  2. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
  3. There could be a vacuum leak.
  4. There could be a fuel pressure or delivery problem

The battery Keeps dying (It’s a new battery not even 2 weeks old) and whenever I charge it or get a jump from my other car it cranks but won’t start.

I did change the engine fuel injectors to my new ones since they are 5 months old only and a good brand. I tested them out and they all have the same resistance. Also, when the engine was running there is a RAPID clicking sound coming from the engine.

Could it be a stuck fuel injector? No mechanic would touch it and it’s been sitting in my driveway for a few weeks now. I will give a great tip to whoever help me figure this problem out. Thanks

I had a 2004 Pacifica. The first thing I don’t understand is your statement “I took the intake manifold out, it was full of gas near the carburetor and it was a lot of it.” If that engine has a carburetor, it is a rare one indeed. It does have a throttle body and I presume that is what you are referring to. Nevertheless, it sounds like the engine is getting way too much fuel. You bought a pig in a poke off eBay and have no idea how (or if) the engine ran before. My next step would be checking fuel pressure while cranking.

Thanks old_mopar_guy I appreciate the help! Yes, that is what I meant. “throttle body” I will check the fuel pressure but I will need to buy a T to attach to my gauge at the fuel rail since pacifica’s don’t have the direct area where you can plug in the hose to test for pressure. Great tip and Thank you so much!!

Also, the engine block have 90 days warranty on it and also the company I bought it from they are amazing and out of 5K engines they sold they have 5K shiny star reviews, I doubt it’s that but good to know!

Might also want to isolate the clicking sound. Stethoscopes are inexpensive.

The flooding might be caused by a defective fuel pressure regulator on the fuel pump.


Have the fuel pressure tested.