Unlike GM pumps that often quit while driving, Chrysler pumps almost never do that. When they fail, they fail to start up when you start the engine.
First check for diagnostic fault codes. Two common causes could be a crankshaft position sensor that is starting to fail or has an incorrect air gap, and a MAP sensor that is reporting incorrect values. Be aware that as long as the MAP sensor's readings are within the acceptable range, it won't set a fault code even though those values might be wrong. Until it fails completely, you would have to observe live data on a scanner during a test drive to see if the readings seem incorrect.
If there are no codes, a good place to start is by installing a fuel pressure gauge and hooking it under the wiper arm so you can watch what happens when the problem occurs. If pressure drops off, suspect a plugged screen in the gas tank. The clue is the engine will run better during periods of acceleration and will run worse or stall when more fuel volume is pumped which is during coasting. For engines with the fuel pressure regulator on the fuel rail on the engine, you can disconnect and plug the vacuum hose going to it as a test. That will cause black smoke from the exhaust but it will raise fuel pressure and cause the pump to pump a lower volume of fuel which can get through that plugged screen without a significant loss in pressure.
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Friday, June 10th, 2011 AT 3:31 AM