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Dont know what the prob is....


rojamz's Avatar
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04-18-05, 07:42 AM   #1  
rojamz
Dont know what the prob is....

Have a 97 Nissan pickup. When driving in all gears except last (fifth) one, the engine put puts and jerks like its not getting enough gas or air. Changed fuel filter, no help. Before these problems started, I replaced alternator. Was having none of these problems before this. Any tips on what my problem could be. Also, puffs of black smoke come from exhaust when engine is jerking and hesitating. Am at my wits end! ANY advice will be appreciated...

 
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04-18-05, 10:08 AM   #2  
How many miles? When was the last time the O2 sensors were changed? I'm no mechanic here, got car problems of my own, but it's something to consider.

 
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04-18-05, 12:03 PM   #3  
rojamz
Its got 112,000 miles on it. Never changed 02 sensors. Do you know if there a way to check the 02 sensor yourself to see if its bad?

 
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04-18-05, 03:51 PM   #4  
Again, I am no mechanic here so I'd wait for a moderator to reply but I think you could go to an Autozone and see if they can pull any codes off of the car's computer for you. I don't suppose you've got any check engine lights on in your dash? Even if you don't, Autozone provides that service for free. If your car's engine is running rich or not, it should let you know. Also, a mechanic could run their diagnostic equipment on it, but that'd cost you about $50. I'm sure there's another DIY option out there, I just don't know what it is exactly. At any rate, if you've owned this car for all of its 112K miles, you're overdue for new O2 sensors anyway... I'd say about 50K miles overdue (depending on your specific car's recommendations) so it certainly couldn't hurt. Shops usually charge about $125 per O2 sensor (ballpark) but if you're not bad with a wrench (a jack, and a couple of other tools) you could save on the labor charges and DIY.

 
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04-24-05, 04:10 PM   #5  
oldmedic
Rough running after alternator replacement

Rojamz, your problem may very well be with the emission control computer. Having replaced the alternator the battery was disconnected for an extended amount of time so the engine computer has lost its memory. Unfortunately this can mean a trip to Nissan to reprogram the computer. Should you need to disconnect the battery in the future Napa makes a cigar lighter plug in with a 9 volt battery that will hold the computer's memory. oldmedic

 
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04-25-05, 12:59 AM   #6  
neither...

...O2 sensors or disconnecting the battery properly will cause what you describe. black smoke indicates too much fuel which may have several causes. a faulty ignition or way too rich a mixture could cause the black smoke. follow the cause of the smoke to win here...first, does the check engine lamp come on? if so, have it checked and post the codes here for explanation...auto zone and others will check the codes for nothing, just don't buy any parts from them and post the exact letters and numbers that they give you and someone here will help decipher.

no light on? then checking fuel pressure is first...if that's ok, then things start getting more complicated...things like wire chafing and such begin to come to mind. also...nissans are VERY sensitive to ground problems...they tolerate very little resistance to computer circuits and go nuts hwen grounds are compromised. without a wiring diagram, a DVOM and very good skills at using it and measuring voltage drops, you'll need a pro for this level of diagnostics.

 
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