My 99 Tacoma has developed a misfire at high RPM that limits it to about 4300 RFP. It ONLY happens when the engine is warm and occurs under any engine loading condition (in Park, pulling a load, going downhill with no load, etc). There are NO engine codes. I have changed the plugs, plug wires, coils, PCV valve, fuel filter, air filter, gas types, etc. The dealers have NOT been able to isolate the problem and found no problems with fuel pressure. They offered to "experiment" by replacing the computer, fuel pump, or "other" components. I don't want to pay for their play time. When cold the engine will rev to red line with no problem but once warm it misfires. Any suggestions????

My 98 Tacoma will back fire everyonce in a while. It might be close to the trouble you are having. My uncle is a mechanic and he thinks the Catalytic converter is getting stopped up. My truck has had a code show up and go away.