Auto Scanner
Larry Rubenstein
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Q: I have a 2000 Dodge Ram pickup, two-wheel drive, 5.9 liter engine. It starts up and idles fine, but when I go to give it gas, it cuts out and I lose all power until I let go of the gas, then it gets the power back. When I start to lose power, I'll give it more gas then it starts making a popping noise from the plenum. This happens when it's cold and hot. I have no engine codes, but I've changed a few of the sensors, idle air control motor, throttle position sensor, crank sensor, oxygen sensor, and also the water pump because it was noisy. I also changed out the wires, plugs, distributor cap and coil. I am all out of ideas. I've brought it to the garage, and they can't seem to find the problem.
A: A few things for you to do: Put the car back on the scanner, and look at the fuel trim numbers. Look at the O2 numbers, report back to me or any other knowledgeable tech with those numbers. Also look at fuel pressure and fuel volume. You may want to ohm out the coil, as well as the condition of the coil tower and coil wire. The last thing I want you to do is take a good look at the coil wire for burn marks if it is routed too close to the exhaust manifold. You didn't mention the condition of the distributor rotor.
Q: I was wondering if you could clarify an old wives' tale for me. I was told that you should never pull into a gas station for fuel when you see the delivery truck dumping gas into the underground tanks. I was told that the contaminants in the underground tanks get all churned up and that the gas pumps puts all that junk into your vehicle. Also, how about gas in the underground tanks from a gas station that closes for two to three weeks while they go on vacation? Does fuel get stale after sitting in the underground tanks and the contaminants get into the pumps?
A: The old wives' tale is accurate and true concerning getting gas while a delivery truck is dropping a load of gas. In an underground fuel tank, there is a pickup tube that is set a few inches from the bottom to accommodate settlement on the bottom of the tank. When getting a load of gas, the tank does indeed get churned up and the suspected bad fuel may get into your car except for a filter at the pump which strains out most of the problems. If you notice, I did say most. Water can still get through the filter and ruin your day. As far as fuel going stale, the fuel will not go stale after a two- to three-week sit, it will take much longer.
Car Care Tip: After having your car repaired, drive it around the area of the service facility a little, just to be able to return if something is not right.
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Larry Rubenstein is a master technician who owns a North Shore service station. His column appears every Saturday. Write to Larry at The Salem News, c/o Auto Scanner, 32 Dunham Road, Beverly, MA 01915, or send e-mail to scanauto@aol.com.
