Fuel Pump? MAF? Inlet Temp Sensor?

[Bretticus]

Out of the blue my xterra decides to buck and jump and bog hard when i push the gas. Dude, no check engine light. So, since the plugs are only 20K old and everything else is suspect, I change the Cap, wires, rotor, air filter (which has been changed every 5Kto 10K since we bought the car) and a fuel filter (old fuel filter showed significant quantities of trash). Car drove fine cold and again, it got hot then got ugly. Lost power and bogged when the gas was pressed... Any gear. So, left it sit all day and got a code reader and tonight the best it says is the knock deal (O325) yeah, it's gonna say when the engine jerks good... THe Piezo will squirt some voltage and trigger the ecu. Suprise, The engine is jerking subsuquent to what ever is making it mess up. Yeah, Now, tonight with the code reader after allowing the car sit all day I started it. Checked codes. Only code of value, it seemed, was the P1320 (ignition issues with the ECU). Again, the ecu will have a hard time if either there is no air at the right time or no fuel to burn. we show a P0300 "random MisFire"; No kidding, I heard it randomly misfire . Again, Likely due to the real problem. The cool thing is no MAF or Temp sensor codes... Bad side is that it seems like the darn fuel pump may be going bad. You know, the first thing i did sunday when it first messed up was... fill it with a full tank of premium Exxon... No better! time for the fuel pump to show it's colors... Anyway.. Tonight, We (the wife and I) now turn off the engine and clear codes and restart it. All we got was the O325 code, but if the engine shakes, the Piezo element should squeeze voltage and flip a code accordingly.. right? So now we let it idle for 20 minutes until it starts missing real good sitting in the driveway. Now, the engine is good and hot. We clear codes and go to ON and see whats up. NOTHING. Yep, no codes. So we disconnect the reader, turn the key to off and try to restart the car. guess what... it wont start now. it just turns over..... like my bronco when the fuel pump kicked the bucket. Now we're letting it cool. IF this b starts cold, i'm going to bet a salary pay check it's the fuel pump... I did fill the tank full with premium Exxon Sunday... Murphy just may have me by the nads what do you think buds?

[tmorgan4]

I just replaced my stock Pathfinder pump with a Walbro 255 for some more flow. It took all of 20 minutes and the pump was less than $100. I've still got my old factory pump that worked just fine but it's probably not worth putting a pump in with 120k miles on it.

[NM50]

It sounds like you have a plugged catyitic convertor.When cold and no backpressure they run ok. After a cold soak they back up and cause a misfire,during warmup.