92 LS400 rough idle and bogging

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Dec 18, 2014 | 04:07 PM

xwilliams

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From: texas

92 LS400 rough idle and bogging

Hello gents. I just got a 92 LS400 from a friend recently. It had about a 1/4 tank of gas so i decided to run that out before I put i put new fuel inside. When the time came to refuel, i used premium and added a bottle of gas treatment. As soon as i pull off the car dies. After a few tries it cranks and enters "limp mode". So far I replaced the fuel filtet only. Wanted advice before I started throwing money at it. Also Im leaning towards it being a MAF problem because thats the code that came back and I unplugged it a little while ago and it started running a bit smoother but still no power really when I push the gas. Any help would be appreciated.

Dec 18, 2014 | 05:19 PM

sha4000

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Why don't you trying cleaning the MAF and unhooking the battery for a about 30 minutes. Then put everything back together and see how it runs.

Dec 18, 2014 | 07:08 PM

cobalt91

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From what I have read you dont want to clean MAF sensor on pre 95 ls400. These older models use a different kind of sensor that is really sensitive to cleaners.

Dec 18, 2014 | 10:16 PM

xwilliams

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What about soaking it in alcohol.and let it dry for awhile

Dec 19, 2014 | 12:48 AM

PureDrifter

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no. it uses plastic in it that is sensitive to most all solvents.

sounds like the gas treatment may have been the cause. what did you use? I would try to get some fresh gas in it.

Dec 19, 2014 | 08:57 AM

xwilliams

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I drained all the old gas because i thought the same thing. (A full damn tank. Smh) and put in about a quarter tank of fresh gas and still the same thing.

Dec 19, 2014 | 10:15 AM

bgalarpe

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From: TX

What about replacing the spark plugs...maybe it got fouled by the old gas and the treatment.

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Dec 20, 2014 | 09:55 AM

sha4000

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I apologize for recommending to clean the MAF which is actually an AFM ( Air Flow Meter ) of the Karman Vortex kind which can't be cleaned. All you can try to do is spray some compressed air in there and hope it fixes it. I would look for a known good one on Ebay or somewhere else if it is in fact that part that is having issues. Maybe a junkyard.

Dec 20, 2014 | 02:01 PM

#10

xwilliams

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From: texas

I took the cover off to change spark plugs and notice part of the timing belt is frayed. So im going to sit it up until i get someone to change it. Thank you for your help gents.