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dddddd
Dodge Dakota
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3/20/2006
19:09:05
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 Subject: running like crap
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Message:
i have a 2000 dakota with a 3.9 and auto tranny. For the past few weeks it has been running like crap at certian times. It will start up fine and everything and drive good, but when i am at slow speeds and low rpms it will SOMETIMES spit and stutter and backfire into the engine, the exhaust it really hot and rich at these times. It put up all o2 sensor codes so i bought 2 new sensors and replaced them, now the check engine light comes on b/c of the first o2 sensor for some reason. When it starts to run bad i shut it off and restart it and it runs good, for a while. What could this be: clogged cat or bad pcm? or????????
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Terry
Dodge Dakota
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3/21/2006
00:36:40
| RE: running like crap
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Message:
Check for vaccuum leaks. They can cause both the rough idle, and the backfire.
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Scott C.
Dodge Dakota
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3/21/2006
19:27:28
| RE: running like crap
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Message:
a vacuum leak will cause a rough idle not a backfire.... backfire comes from loading up on gas and it lays in the exhaust and then eventually it will light off cause the exhuast can suck in air on a rpm drop(like nailing the gas and then letting off) the cold air will hit the hot air and the fuel laying in the exhaust you get a pretty good BOOM...
but in your case with it spitting and sputtering... could have a problem with it loading up on gas... like fuel injector stuck open... or losing spark at the plugs or in the cap or through the wires... if the vehicle is loading up on gas and the O2's see it, the O2's will try to get the vehicle to lean out... they can only make the vehicle lean so much by having the computer pulse the injectors less then normal.... now if you got an injector stuck open and it dumping gas it will lean back so far but if the O2's still see rich conditons and they are still trying to cut back... the computer can throw a false code for the O2's.... so you can be chasing the wrong problem playing with those O2's when the problem is somewhere else... so basicly what i would do is pull the fuel rail up trun on the key run position and see if your injectors are leaking down.... if not leaking with key on have someone crank over the engine but remember to disconnect the ignition coil so the truck doesnt try to start... while the other person is cranking the engine over with key watch the spray patterns of your injector they could be dumping to much fuel cause by a bad regulator or hanging open while being pulsed by the computer and dripping once it has a chance to open up...
Scott C.
Royal Auto
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dddddd
Dodge Dakota
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3/21/2006
19:45:56
| RE: running like crap
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Message:
thanks guys, so u dont hthink it is the computer? b/c we were looking at the voltage going through the computer (using our GENESIS scanner) and it kept jumping and going negative on the o2 sensor, i think.
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Scott C.
Dodge Dakota
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3/21/2006
19:57:33
| RE: running like crap
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Message:
your O2's do that... that means your O2's are switching properly.... i believe but i could have it backwards.... an O2 sensor goes negative voltage when the system goes to rich and goes positive voltage when the system goes lean thats on the front O2's
Scott C
Royal Auto
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dddddd
Dodge Dakota
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3/21/2006
20:07:57
| RE: running like crap
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so u think i should clean out the fuel system maybe? or is it a comp prob controlling the injectors
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Scott C.
Dodge Dakota
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3/21/2006
20:11:12
| RE: running like crap
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cleaning the fuel injectors might help... i dont believe its a computer problem( i see you posted a computer question cause i replied to it) i believe you got a lazy injector or injectors or they might need cleaning cause of carbon deposits ....
Scott C.
Royal Auto
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HOOSIERDAK
Dodge Dakota
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3/22/2006
03:27:39
| RE: running like crap
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Message:
Check on the tail gate to see if if has dakota or dodge on it, thats the problem right there
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dddddd
Dodge Dakota
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3/22/2006
19:25:06
| RE: running like crap
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Message:
if it was fuel related, like a bad fuel pump, why would it be throwing a 02 code.
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dddddd
Dodge Dakota
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3/22/2006
19:34:07
| RE: running like crap
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Message:
o , i c. could it b a bad fuel pump tho?
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dddddd
Dodge Dakota
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3/23/2006
16:17:04
| RE: running like crap
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Message:
could it be my iac, and what/where is an iac
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dddddd
Dodge Dakota
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3/23/2006
18:41:39
| RE: running like crap
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Message:
well i just did a tune up on it, wires cap and rotor, the plugs were good. still having the problem. what to do. could this b the fuel pump/in tank filter. Keep in mind still that when it runs crappy if i shut it off it will usually run good for a little bit.
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