P0304 - 2004 toyota tacoma 3.4 v6

While driving recently I lost power due to a cylinder misfiring. When I got the engine codes they showed cylinder 4 and 5 misfiring. I have tested the wires, replaced all of the spark plugs, replaced coils after switching them to verify if one was bad or not, replaced all the fuel injectors and I am still getting the p0304 code. Any clues on what to test or fix next?

 

How many miles on the truck?

 

188,000

 

Another question. What plugs did you use?
When you say that you are still getting the code, did you disconnect the battery to clear the codes?

 

NGK and yes

 

Do a compression test

 

If the compression is within spec, the misfire cause will most likely be a bad injector.

 

Fuel injector? I have already replaced them and everything I see says they are a common misdiagnosis.

 

check your O2 sensor, upstream.

 

You can scratch out ignition right off the bat as 5's coil is connected to 2 and 4 is fed from the coil on cylinder 1.



Probably not a head gasket unless you blew both at the same time. Compression check is good and a fuel pressure check just to be sure. Could be a clogged filter or bad fuel pressure regulator. Both can be had for under $100 and are easy swaps.

 

Ok,You should do a compression check.

 

FSM DI for misfire attached and all supporting docs. I skipped the Fuel Injector testing docs as you've already replaced your injectors.

 

Ok thank you all.