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Sputter; slight vibration (Fuel System?)

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Old 06-12-2003, 09:59 PM
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Default Sputter; slight vibration (Fuel System?)

Ok from the top...

When I'm idling in park, pop the hood, and hold on to the engine I feel slight bursts of vibration. I can also slightly see the vibrations. It can be best explained as a sputter or short bursts of lost fuel. I'm not sure, I just threw "fuel" in there because thats the first thing that comes to mind. My ignition system is just fine, except my plugs may be a little darker than usual due to nitrous passes. But I changed the plugs about a month ago and havn't been that crazy with the laughing gas since.

I just put a new o2 sensor in (NAPA, ok so far) and dumped some more fuel injector cleaner in yesterday. So heres what I'm thinking:

1.) Clean fuel rail fittings, then clean injectors by hand.
2.) Fuel Filter? (currently Fram filter I put in this previous winter)
3.) Fuel Pump? (don't know much about my fuel pump at all)
4.) I'm going crazy.

Inside the car, sitting at the wheel, you honestly can't feel the vibrations unless you're being extremly anal and waiting for the slightest bump. I did push the thottle in slightly when at the engine compartment and after holding it at a particular rpm I could sometimes feel small twitches or sputters.

So what do you all think? Am I finally going crazy???? Or do I simply need to go through some overhaul?
Old 06-13-2003, 12:54 AM
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Mine does the same thing.... I think. Do you run synthetic oil or have you flushed your oil lately? Fuel injectors could be slightly off also. One could be injecting fuel more/less efficiently. How bout your pcv valve?
Old 06-13-2003, 12:31 PM
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I recently switched over to synthetic oil, so I'm sure there are traces of conventional oil left. But I don't see how that could be a problem, then again I may be wrong.

You may be right, one of the injectors is probably dirty (or maybe more). :?

Also I'll be sure to check the PCV valve today and inspect the o-rings.
Old 06-13-2003, 05:51 PM
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It is safe to mix conventional and synthetic. What I was refering to was synthetic keeps engines much cleaner then conventional oil tends to.
Old 06-13-2003, 07:02 PM
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Small world!! I was having that same exact problem a few weeks ago! Except you explained it better. I could feel the vibrations throught the pedals at idle, and it was not constant, but sporadic.

What surprised me is when I changed to my Taylor wires and new plugs about two weeks ago, I haven't had that problem anymore! I'm happy it'* gone but I wonder if it is only temporarily fixed. I did change my PCV, fuel filter, and O2 sensor in January, so maybe my plugs and wires were the last two things needed to be changed. But I could be wrong.

How should I clean fuel injectors since it wouldn't hurt to do that anyways?
Old 06-13-2003, 07:23 PM
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Go get a compression test done on your car. That would tell you if one of your cylinders is not getting enough , spark, fuel/air. Its a good idea I think I am going to get mine done some time next week.
Old 06-13-2003, 07:30 PM
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Should I worry if I can see my engine vibrate at idle? I thought that was normal.
Old 06-13-2003, 07:41 PM
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When I replaced my plugs last month it was only a temporary fix.

Russian, I totally forgot about a compression test. Thanks for the reminder!

I cleaned out the PCV valve (rings and all), but she still does it.
Old 06-13-2003, 11:44 PM
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I had that problem in my 89. One of the six plug wires was going bad, and it would sporadically ground out against the chassis. You could see the spark whenever it happened. It didn't happen every revolution, but it would happen like once a second, but more randomly.
Old 06-14-2003, 01:20 AM
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I doubt its anything to do with his ignition system. I think its recommended every 60-80k miles to have fuel injectors properly cleaned and balanced? I havent done mine yet and i know its never been done before. It would probably make her run quite a bit better. Like $80-110 bucks I think.


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