2.7 Tacoma misfires when cold

Hi I have a 2007 2.7L tacoma that is misfiring when cold. Cylinder one misfiring originally and I replaced the plugs and coils. Cylinder one would still misfire and throw code po301 until the car warmed up (even after coils and plugs) but this issue randomly went away several months ago. Now it is back but on cylinder 4 this time. I would’ve thought that if this was a head or head gasket issue that it would stay with the same cylinder. Injectors we’re also cleaned and swapped around but that didn’t fix the cylinder one issue.

 

If you wana check for coolant getting into the cylinders pull the plugs and coils, get a cooling system pressure tester (many auto parts stores will rent these if you don't want to buy one), presurize the cooling system to about 15psi, let it sit like that a couple hours and then look for coolant in the cylinders.

 

Looks like you already did a good diagnostic, and it's following cylinder 1 clearly. With temps, metals expand contract area. Could just be a slightly loose connection on the cyl 1 coil connector, and after warm up is able to make better contact? If you swapped all that around and cyl 1 won't change, I would start looking at connections.

 

Sorry for the late response. Cylinder 4 is the main problem now; nearly every time I start it it throws a misfire code for cylinder 4. Sometimes when it shakes really bad it will throw a code for 1 and 4. I just tried starting it for a couple seconds and then pulling the plugs and cylinder 4 plug was soaked. I’m 90% certain it was coolant because it didn’t smell like gas and we tried lighting it on fire and it didn’t burn. I’ve also done a combustion leak test on the radiator but it passed(no combustion gas in radiator). Compression is around 120 all around