A coupe of weeks ago, I posted this problem (which was an easy enough fix):
https://www.scionlife.com/forums/sho...d.php?t=200949

Tonight, I boosted into 4th and my CEL started flashing. It went away after about 15 seconds. This isn't good, I know, but I got it home fine and it didn't seem to have any driving issues. I didn't feel or hear anything unusual, but the consensus seems to be that I misfired. I didn't get any codes to read, which bothers me too.

When I got home, I disconnected the battery to clear the ECU and started her back up with no issues, but my STFTs were waaaaay too high, at around +15 - +18 while idling. LTFTs were zeroed out.

My first thought is that when my charge pipe blew off and I dumped a ton of gas (see previous thread), I think I've fouled a plug. Another thing to note is that my map runs a tad rich (done by an Evo tuner), and I backfire if I hard accelerate, let off the gas, then get back on it. I usually get a loud pop once I get back on the gas, but only if I've done a hard acceleration. Maybe my cat's going too.

Regardless, she's parked and going to the shop on Saturday, but what are y'alls thoughts?

Thanks as always.

 

was the car misfiring right before the cel began flashing?

go buy some plugs there like $3 each

 

I felt a slight stutter, but it didn't feel like a serious problem. If anything, it just felt like a poor shift.

The main thing that bothers me is the short fuel trims and how they've jumped way up, even after a reset. Is that indicative of bad plugs? Why is my ecu adding so much fuel now?

I'll start by changing out the plugs to see what happens.

 

what were your wideband readings around the time of the misfire

 

They were on the rich side, 11-13. But like a said in the original post, my map runs rich after a hard acceleration, sometimes pegging 10 for a split second. It's like the injector duty cycle continues for a moment after I let off the throttle, and when I get back on it I backfire the excess. Not ideal, but running a cat along with pull through maf add to the issue I think.

What about the increase in STFTs?

 

check ur spark plug for oil. if there is any oil its not looking to good. but i could just be that u need new plugs

 

Nope, no oil on the plugs. They were in good condition, but I swapped them out for new ones.

I think the problem is the harness crosstalk that occurs with the FIC under high RPMs. Looks like I need to do the resistor mod.

I got the STFTs to clear after swapping the plugs. Just needed the battery to be disconnected a little longer.