Here's the history:

Went out to eat dinner and drove the car. Was inside eating for maybe 1-2hrs. Got into car and I get the blinking CEL. After a couple seconds the blinking CEL goes solid and the car becomes driveable. The car drove fine on the way to the restaurant.

I get the car home and pull the codes. Misfire on 1, 4, and random misfire codes.

Next morning I change the spark plugs for OEM NGKs and put a bottle of fuel injector in the gas tank and put some Chevron gas in the tank (about 1/2 a tank). Thought it could be bad fuel.

It misfires a lot less frequently after that and now it only really misfires at WOT (wasn't beating on the car, just testing it and I did not rev the car past 5k) and at idle. But it wasn't doing it enough to bring a code for about 4-5 days. Because of this I thought it might be the injectors. While waiting for the injectors to come in I did the MAP whack and cleaned my IACV.

So I purchased some used JDM AP1 injectors (these should work on a USDM AP1 right?) and installed them tonight. Now the car is misfiring worse than ever and the blinking CEL blinks permanently. The car is not drivable. I pulled the codes and I'm not getting any cylinder specific misfires, just random misfires.

Now I've purchased some used coil packs from a MY05 and will swap those. If this doesn't fix the problem I don't know what to do next. Could it be my fuel filter or fuel pump? I have a Walbro fuel pump still in there from when the car was Supercharged. Could it also be my cat?

I had the valves adjusted about 3k miles ago so I don't think there was any piston/valve clearance. I baby the hell out of this car. I don't track it or engage VTEC all day, it's my daily driver.

It's just a sick problem. You basically take a check list and go down it. If anyone has any recommendations of what to do after coils it would be greatly appreciated. I'll probably do a compression test but after that I'm clueless and draining money on this is exhausting. Do you think I should put my old injectors back in?

Sorry if my thoughts are all over the place. I'm extremely frustrated right now.

 

Wrong forum sorry. Can a mod move to UTH?

 

Here's a thought, your injectors are bad and you'd bought bad USED injectors as well, it happens. Beside that, I don't know what to tell ya as many people are still trying to figure out what's going on.

 

Update: I put the old injectors back in and the car runs 100x better than with the JDM injectors. I also cleaned the tips and tops off of a little bit while I had them out. Perhaps the JDM injectors require JDM clips or something, but the car ran like complete ass.

I engaged VTEC all the way to red line a couple times so I think fuel pressure is fine and there is no sputtering or misfire at WOT. The misfire is only at idle. Next step will be to replace the coil. I'm going to replace all of them at the same time for peace of mind because if it is infact the coil who knows how long before the other ones go bad too...

While I wait for the coils to be shipped I'll check the voltage on the TPS and make sure the knock sensor is tight. I'm pretty sure it's not the knock sensor though because I'm able to rev fully to redline and VTEC engages.

 

If you have access to a scan tool with a data list i would try watching the misfire counter. See which cylinder or cylinders are missing the most. If it turns out to be 1 and 4 then swap those coils with 2 and 3. If that doesn't work then i would do the same with the injectors.

 

Probably time for new USDM injectors.

 

Wow. Exact same problem as me...so could be the injectors, huh?

 

If both of you follow the step by step misfire troubleshooting guide, there is a 99.9% chance you will find the solution.

 

So it wasn't the injectors after all. It turned out to be the coils. Replaced all four and problem fixed.