1998 Dodge Ram problem: feels like running outta gas, but h

  • 1 POST
  • 1998 DODGE RAM

Engine Performance problem
1998 Dodge Ram V8 Four Wheel Drive Automatic 115000 miles

The problem is: the truck feels like its running out of gas but has gas in it. Here's the scenario- other than info above, the truck has brand new motor and transmission. Its been sitting around for 2 years. Has new spark plug and filter and oil changed. Someone once mentioned -changing fuel injectors? What are the possible causes to this problem? The truck runs smooth other than- every once and a while it does the motion, like its going to run out of gas or stall, then if you press the accelorator it picks back up again. Sometimes it takes a while for the truck to get going again. Terrible in traffic-bumper to bumper.
what other information could you need to make a possible diagnosis? THANKS!

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Thursday, June 4th, 2009 AT 7:41 AM

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Fuel injectors are not the problem. Chrysler has always had very little trouble with them, plus, do you really think eight of them are all going to fail at the same time?

Also, fixing a running problem on a Chrysler product by replacing the fuel filter is also almost unheard of.

Try disconnecting the vacuum hose from the fuel pressure regulator and plugging it. The truck won't run perfectly, and there might be some black smoke out the tail pipe, but if it doesn't stumble anymore, suspect a collapsing pickup screen in the fuel tank.

The screens tend to collapse when the largest volume of fuel is being pumped which is during coasting. Unplugging the regulator mimics loss of manifold vacuum as in when accelerating. Fuel pressure will go up significantly, hence the rich mixture and black smoke. High pressure is caused by the regulator becoming more restrictive, thus less fuel flows through it and back to the tank. The amount of fuel used by the engine won't change much, but there will be a lot less fuel going through the screen.

I don't think you can buy a new screen. You will either have to get a new pump assembly that includes the screen, or you can cut a slit in the top of it. The external filter will still trap dirt, but you also run the risk of jamming the pump impeller. Chrysler pumps are built to very tight tolerances. It makes them extremely quiet, especially compared to GM pumps, but they're also more susceptible to locking up. When you experience multiple pump failures, the fix is to have the tank steam cleaned to remove microscopic debris. Radiator repair shops can do that.

The screen could be plugged with a rusty-colored mud too. If so, try squeezing out the crud and washing the screen in clean gas.

When you drive with the regulator hose disconnected, the exhaust will be rich for a long time. This is hard on the catalytic converter. If this is the only way you can keep driving, don't plug the disconnected vacuum hose. Leaving it open will allow a little extra air in. Idle speed will be high, but there will be less chance of overheating the converter. The "Check Engine" light will also probably turn on after a minute or two. The engine computer will see the constantly-rich exhaust, memorize a diagnostic fault code, and turn the light on. Later, when the regulator hose is reconnected, the light should go off after you cycle the ignition switch off and back on. The fault code will be erased automatically after about 50 starts.


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Friday, June 5th, 2009 AT 1:50 AM

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