Hey Scotty!!
I have a 2.7L 2002 Toyota Tacoma 250,000 miles and just recently had a P0304 code (cyl 4 misfire). I just changed all 4 spark plugs and swapped cylinder 1 and 4 ignition coils to see if I get the same code but I am receiving the same code. My engine is shaking. What should I do? I bought the truck brand new back in 02 with 0 miles
The compression test should reveal a lot. Let us know.
Check compression to see if there's a problem in #4 cylinder.
I’m doing a compression test this weekend. I had the same issue before at 210,000 miles. I took it to Toyota on November 2018 and now I’m getting the same issue, I don’t think Toyota fixed the problem. Could it possibly be the engine is not receiving enough air?
Could it possibly be the engine is not receiving enough air?
Unless your air filter is badly clogged or there is some obstruction in the intake it does not seem likely.
If your plug and coil are good, it's probably fuel related. Clean your injectors, new air filter, clean MAF, etc. In the last 20 years, how many times have you replaced the fuel filter?
Fuel filter was replaced in Toyota as well, (thermostat, water pump, fuel filter, fuel pump, they cleaned engine head, new head gasket, I believed bored cylinders) November 2018, I’m thinking injectors are super dirty but I also don’t know if I have low compression until this weekend, after 40k miles I don’t think I should have the same problem again
Just completed compression test (rented tool from Oreillys) on a warm engine (drive a couple of miles and turned off engine). Received compression below:
Cylinder 1: 140
Cylinder 2: 140
Cylinder 3:140
Cylinder 4: 138
Could it be possibly bad head gasket or bad intake? This issue only happens when engine is turned off and turned back on warm. I can literally drive for hours if I turned the engine on cold (will not have misfire)
Took vehicle to Toyota Dealership, they recommended to replace all injectors and new MAF sensor, do you think all injectors should be replaced or possibly even clean the injector for cylinder 4?
Replace them all. Don't go to a dealership unless you like getting ripped off. If the MAF is suspect, remove it, clean it, check it for conductivity and resistance and re-use it. Why buy a new one if you don't have to?
Update: it was a bad fuel injector. Replaced all and just put in a new MAF sensor. Vehicle is running brand new!! However, just got a new code P0401
New EGR valve.