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Dually Engine \  dually running rich and randomly misfiring

dually running rich and randomly misfiring

Dually Engine Dually Tech
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replies 56
following 7
 
jessejames7575   +1y
its a 99 dually with the 454..just started running horrible..sometimes can drive 100 miles,,sometimes 1..then it starts missing and running ruff. and u can smell gas..so i hooked it to my snap on mt2500 and it says driver bank running rich...ive changed..distibutor cap..button..pick up coil..plugs..wires..ignition control module..map sensor..coil pack..has brand new fuel pump and filter..and #1 injector..after changing injector..ran stronger than ever for about 5 miles..then backfired and started doing it again..i bought the truck in tx in december and drove it to ky..but when i read live from my scanner it will randomly say misfire..cylinder 1 then maybe 3 and 5 then maybe 8..just jumps around..then sometimes no misfires..idles fine..sounds great..even at idle u can floor it and no misses..also checked compression and its fine..and no fluids mixed as far as a head gasket or anything..and doesnt run hot...any suggestions would b great..its the schoolnu dually..im gonna post pics if i can figure out how
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jessejames7575   +1y
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jessejames7575   +1y
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bigcat   +1y
Take the O2 sensors that are before the cats and switch them from side to side and see if the missfires switch sides on the scanner. if so change both upstreem O2s.
someotherguy   +1y
Then start saving your milk money to replace injectors with the improved design Bosch units and also the regulator while you're in there. Price has crept up on these so you're looking at around $500 total in parts once you get injectors, regulator, gaskets, and shipping...

Richard
brianbgboy   +1y
i have a 2000 model that had a very similar issue that came about 1000 miles after new bosch injectors and regulator. it ended up a cam shaft sensor. its in the distributor. made it run a hell of a lot better than ever, so i guess i had issues for a while with it. your truck was built here in louisiana by a guy in houma named scooby. nice truck for sure...
someotherguy   +1y
Crazy...first time I've heard of the cam sensor on a Vortec going bad. Pretty simple item.

Richard
jessejames7575   +1y
Still haven't had a chance to do the o2 sensors. But from I'm seeing the cam sensor and pick up coil is the same thing. I looked up both parts. And exactly the same. And I've swapped it and everything else twice to make sure I didn't get any bad parts. I'm gonna try the 02 sensors tommorrow. And see if that does anything. I sure hope so. Its too damn nice outside not to b out driving this thing
jessejames7575   +1y
Ok so I just replaced both upstream 02 sensors and egr valve. Truck ran better than it ever has. For about an hour then started acting up again. Only things I haven't changed r the maf sensor. The 2 that's on the throttle body and the one in front of the egr valve. Or the rest of the injectors. But what I changed yesterday felt like it made a huge difference for just a bit. Any other suggestions??
someotherguy   +1y
Really taking a wild guess here, sounds like it's not running rich because of O2 problems, but the rich running is fouling up your O2's and making the situation worse as this happens.

Richard