1999 3RZ Misfire Codes P0300, P0303 NEED HELP

[SDsurfx]

Gonna start ordering parts for this job, anticipating having to send the head off to a machine shop.

I’m not sure if a simple valve adjustment will fix the problem as the intake valves on #3 are leaking (must be the valve and/or valve seats worn).

Anything I’m missing here?

Toyota 4Runner,T100,Tacoma 2.4L 2RZ, 2.7L 3RZ (95-04) Full Gasket Set - FGS9039 (head, intake, exhaust)
Toyota 4Runner,Tacoma 2.4L 2RZ / 2.7L 3RZ,2TR,2TZ Engine Cylinder Head Bolt Set HBK957Head bolts
Fresh coolant (though it’s only got 5k on it)
Fresh oil/filter (due for change anyway)
New Plugs (old ones fouled due to misfire)

 

[MaineRunna]

Gonna start ordering parts for this job, anticipating having to send the head off to a machine shop.

I’m not sure if a simple valve adjustment will fix the problem as the intake valves on #3 are leaking (must be the valve and/or valve seats worn).

Anything I’m missing here?

Toyota 4Runner,T100,Tacoma 2.4L 2RZ, 2.7L 3RZ (95-04) Full Gasket Set - FGS9039 (head, intake, exhaust)
Toyota 4Runner,Tacoma 2.4L 2RZ / 2.7L 3RZ,2TR,2TZ Engine Cylinder Head Bolt Set HBK957Head bolts
Fresh coolant (though it’s only got 5k on it)
Fresh oil/filter (due for change anyway)
New Plugs (old ones fouled due to misfire)

Maybe a timing chain and guides if you feel like it.

 

[SDsurfx]

Well she’s back on the road. Got to a point where I was running into problems I hadn’t anticipated (broken timing chain guide), and was using my vacation wrenching when I’d rather be surfing.

Had a shop finish it off:
1. Cylinder head rebuilt (#3 intake valves were in fact BAD)
2. New timing chain and guides
3. Fresh oil, coolant, and gaskets

Runs great. The intake manifold was filthy, can’t believe it was even running much less getting 20ish mpg on only 3 cylinders!

No more P0300/0303, CEL, or rough idle.

 

[Alan in Alabama]

SDsurfx, Thank you for your last follow-up post where you told the final outcome of finding the problem and having it repaired. I've followed on various forums through the years and the worst threads are where someone asks for advice, gets it, and then disappears, making the thread much less useful for future people who have the same problem. And many times not even a thank you for expert, free help.

I did a search for 3RZ problems and found this thread,