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Guest Message by DevFuse
 

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Stumbling issue


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6 replies to this topic

#1 Manarius

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    1995 Subaru SVX LSi

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Posted 27 June 2008 - 05:52 PM

Maybe someone here will have an idea. I've been having trouble with my SVX ever since I replaced the plugs back in the middle of May.

The problem is this: The car stumbles fairly badly when cold. It also can't find idle and stumbles enough to shake the engine. It will also stumble randomly when warm. Seems strong if I am really hard on the gas. Here's what's been done:
  • Tested to see if the stumble follows a coil - no response from the car
  • Replaced fuel filter Replaced front knock sensor (ECU threw a code - sensor was broken)
  • Greased all coil boots with dielectric grease
  • Replaced MAF with known good MAF
  • Cleaned throttle body with TB cleaner
  • Cleaned IACV with TB cleaner (emptied about 1/4 of the can into the IACV, made lots of smoke)
  • Ran Seafoam through gas Sealed minor exhaust leak
  • Replaced two of the plugs because I *thought* they might look bad.
Here's a video of a bit of my drive to work in the morning:

You can see that the car definitely sounds and acts weird when it's cold. It's not really safe and it's really really annoying. If anyone here has any ideas, please post them. I'm willing to do almost anything to get rid of this.

#2 sea#3

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Posted 28 June 2008 - 12:58 AM

What type of plugs and what did you gap them too ?

SEA#3

#3 Manarius

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Posted 28 June 2008 - 05:35 AM

Are all your vacume hoses connected properly? Test your TPS sensor to make sure its adjusted properly and operating as it should.

nipper

As far as I can tell, yes they are. I tried to find the vacuum leak with a bottle of carb cleaner but no luck. I also just tested and reset the TPS to .48v (spec is .48-.52v)

What type of plugs and what did you gap them too ?

SEA#3

NGK Iridium IX. They come pre gapped.

#4 john in KY

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Posted 28 June 2008 - 05:52 AM

Pull and plug the vacuum line that goes to the brake booster and see if the engine idles differently. A long shot but you never know.

#5 sea#3

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Posted 28 June 2008 - 10:04 AM

As far as I can tell, yes they are. I tried to find the vacuum leak with a bottle of carb cleaner but no luck. I also just tested and reset the TPS to .48v (spec is .48-.52v) NGK Iridium IX. They come pre gapped.


On the TPS it isn't the base voltage you have worry about it's the sweep voltage as you accelerate , the best way to check it is with a lab scope and do a sweep of the TPS . That said if you don't have one , swapping a known good one is the easiest thing to do

On the plugs , don't always assume that the plug gap is correct "out of the box" they are some times set for different models . They also can be dropped and the gap gets ‘adjusted ‘
I know it's a PIA but i would recheck them (0.039 -0.043 in)

Hope this helps

SEA#3

#6 Cougar

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Posted 29 June 2008 - 04:02 PM

Like Nipper suggested, I would check for a intake manifold leak that may be the cause of this. The gaskets on the intake manifold may be failing.

#7 wtdash

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Posted 30 June 2008 - 02:32 PM

Temp sensor?




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