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2007 V6 Limited 4run
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1 Posts
Discussion Starter #1
2007 V6 Limited, 120k.

Getting a P0300 (Random Misfire Detected)

Just replaced plugs, still getting the code. Is very noticeable around 1400-1800 RPM at 50mph.

Any help is appreciated!

Thanks!
 

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Moderator
1998 T100 SR5 2WD
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13,615 Posts
Welcome to the forums! :)

Yer best bet is to perform a diagnostic read of yer ECU and sensors via the OBDII port with a decent/pro level scanner. Depending on what the scan sez, you might need to hook up an oscilloscope to git a better read on what might be causing the misfire. ;)

Has this vehicle been in an accident before? Any other maintenance performed prior to this issue? Any aftermarket modifications installed? What make/model of spark plugs did you install? Do you have any piccies of the business ends of the previous plugs? Any issues with the old plugs? ;)

I take it that you have the 4.0L, 1GR-FE engine? Have you inspected and cleaned the injector grounds? I'm not exactly sure where they would be on the 1GR-FE engine but on the 5VZFE engine they were on the air plenum. Have you been using Tier 1 fuel in yer vehicle? If not, you might want to run a decent fuel injector cleaner through yer fuel system. I really like the BG 44K fuel system cleaner. You might have a dealer near you or you can find them on eBay fer about $15 to $20 a can. ;)
https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/
 
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