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toast · 05-12-2019, 04:49 PM

I think I may have caught it. Did a 15 minute data log of warming up partially in the garage and then driving. Oil and coolant were fully up to temp, sitting at a light and I can feel the car idle sounds funny. Looked over to the laptop and could see the AFR swinging from 12 to 14. Had to blip the gas a couple times to keep the engine alive and pulled over off the road for a minute. Then it all just went away and car was fine.

File is too big to upload to datazap so I have to figure out how to cut it up, but here is a screenshot of the area of interest. Throttle is zero, MAF is pretty constant. MAP starts going all over the place, fuel tries to keep up but then the AFR drops so the fuel drops. This continues in a cycle until I pull over and then when it goes away everything is normal. So either my MAP is flaky or the Dbox is (the MAP connects to the Dbox). From everything I see it looks like the primary O2 sensor is fine.

05-12-2019, 04:49 PM	#14
toast Senior Member Join Date: Jul 2014 Drives: 14 BSP Edelbrock BRZ Location: Lon Gisland Posts: 806 Thanks: 113 Thanked 452 Times in 257 Posts Mentioned: 12 Post(s)	I think I may have caught it. Did a 15 minute data log of warming up partially in the garage and then driving. Oil and coolant were fully up to temp, sitting at a light and I can feel the car idle sounds funny. Looked over to the laptop and could see the AFR swinging from 12 to 14. Had to blip the gas a couple times to keep the engine alive and pulled over off the road for a minute. Then it all just went away and car was fine. File is too big to upload to datazap so I have to figure out how to cut it up, but here is a screenshot of the area of interest. Throttle is zero, MAF is pretty constant. MAP starts going all over the place, fuel tries to keep up but then the AFR drops so the fuel drops. This continues in a cycle until I pull over and then when it goes away everything is normal. So either my MAP is flaky or the Dbox is (the MAP connects to the Dbox). From everything I see it looks like the primary O2 sensor is fine.