1999 Dodge Caravan miss

  • 6 CYL
  • FWD
1999 Dodge Caravan 3.0 engine. At a constant speed of 55 or so the engine appears to miss or shutter then will go away. Also, if I accelerate the miss stops immediately. Very intermittent.
I had code p0172 and took it in to a repair shop. They replaced the MAP sensor but the problem is still there.
Do you
have the same problem?
Thursday, March 31st, 2011 AT 3:56 AM

1 Reply

That code is for one side of the engine running too rich. The best place to start is by connecting a scanner to view the long and short-term fuel trim numbers. If the numbers are real high positive, the computer is adding fuel in response to something. If the numbers are high negative, it means the computer sees there is too much fuel and is trying to do something about it.

You might want to check fuel pressure. If the return line from the regulator to the tank is blocked or kinked, the higher pressure will result in too much fuel entering the engine. An injector that isn't sealing properly can cause too much fuel too but Chrysler has almost no trouble with them.

Since the Engine Computer is capable of correcting a slightly too rich condition, it would make more sense to investigate the misfire you're feeling. It's interesting that it goes away when you accelerate. Normally I'd suggest starting with the basics like spark plugs, wires, cap, and rotor, but you should be getting a fault code for the misfire. Since you are not, you might want to observe if the "shutter" is not engine-related. Shudder is a term used quite often to describe the symptom when the wrong transmission fluid is used. That typically shows up when the torque converter locks up. To test that, drive at a steady speed above 45 mph and hold the gas pedal steady, then tap on the brake pedal for just an instant. You should see engine speed increase about 200 rpm, then go back down a couple of seconds later. If the shudder occurs when engine speed goes down, suspect the torque converter or the wrong type of fluid.
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Thursday, March 31st, 2011 AT 5:31 AM

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