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Vehicle: 1996 Dodge Caravan 3.8 386,000 mi Problem: misfire at mid/light load Codes say Cyl 6 misfire and random misfire. What I've done so far: spark plugs wires coil pack oxygen sensor checked fuel pressure while driving. It does not change and is at spec. Heres the strange thing. The exact same thing happened in January. Thats when I put all the parts on. There was no improvement so I put the old coil pack back on and returned the new one. I drove it a few more times but since we were in the middle of a deep freeze I figured I'd wait to investigate farther. Suddenly the problem completely disappeared. I wrote it off as bad gas. Since then I drove about 10,000 trouble free miles. Suddenly last thursday the problem came back exactly the same. Engine idles fine. you start accellerating at a normal accelleration. first gear is fine, trans shifts to 2nd. All is well. RPMS start climbing and get to about 2400. At this point you feel a vibration and the RPM drops to 2200. If you back off the gas the RPM drops more and the trans shifts to 3rd and RPM drops to 1600. If instead of letting off the gas, you give it more gas it will start backfiring though the intake. If you are careful, you can get it up to 45 which is the lockup torque converter engagement. After the converter locks, any misfires are extremely noticeable and violent. I have not attempted any repairs yet since the problem re-occurred The weird thing about is that in normal acceleration the RPM goes above the problem point and then drops down. It feel like its running out of gas. But I'm not loosing fuel pressure. I don't think I have mechanical engine damage because the problem disappeared for 10,000 miles. besides the plugs, wires, and O2 sensor mentioned above, the only other engine management parts that have ever been replaced on this vehicle are the: camshaft sensor 25,000 miles ago. fuel pump 130,000 miles ago. EGR valve 200,000 miles ago. Obviously everything else under the hood is about 200,000 miles past it's design lifespan. I'm suspecting maybe an EGR issue, because I did get an EGR flow code in the middle of the summer, but it just disappeared. Can a stuck open or closed EGR valve cause such violent misfiring?
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Aug 19, 2014 03:44
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| # ? May 25, 2024 07:02 |
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What are the codes How much do you have into chasing the issue, how much is the van worth, and what would it cost to replace.
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Aug 19, 2014 03:52
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I would hazard to guess ignition or the fuel injector. Can you mash the throttle past it? The problem with a 386k car is that pretty much every electical connection is gonna be corroded and I gurantee your fuel injectors are plugged to some degree. If possible I would pull the fuel injector and see if it looks like its rough shape. failing that, pull and test every wire from the spark plug backwards.
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Aug 19, 2014 04:39
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