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2004 IS300 Manual Swapped
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58 Posts
Discussion Starter · #41 ·
Got the wideband installed yesterday and went for a quick drive, at idle it’s moving between 14.6 and 16 AFR. WOT gets me in the mid-low 11s, partial throttle seems to get me in the mid 13s. If it’s frequently dipping down to 16 at idle that seems to me like it’s possible the engine is misfiring infrequently at idle when the stock ecu is trying to lean everything out. Which is what I suspected before.
I also checked the valve clearances again and the two exhaust valves that were at .009” have moved to 0.010” so I didn’t bother swapping shims. Also moved the cam gear to -3 while I was in there. It feels a little better now, but can’t say there was a huge difference.
Also checked all the plugs and they look good, all of them are white in the center and tan or brown on the tip.

 

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Plug heat range is burning right. It is real clean. You may be a bit to lean at idle. But there is no load. So it is fine. The -3 to -4 should make it more broad on power.
 

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Registered
2004 IS300 Manual Swapped
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58 Posts
Discussion Starter · #43 ·
Plug heat range is burning right. It is real clean. You may be a bit to lean at idle. But there is no load. So it is fine. The -3 to -4 should make it more broad on power.
Yep, glad to see the plugs look good after a couple thousand miles. I think the idle AFR bouncing around is why it feels fine but will occasionally throw a code, but that’s just me guessing at this point. Hopefully the Link ECU will help iron everything out and take advantage of the cams.
 
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