2000 Pathfinder bucking bronco

[tonyw]

I have a 2000 Pathfinder 5-speed with 200K on it. It runs great, well it did..

I went on a short trip and about 20 minutes into the voyage it started bucking like it was fuel starved. Almost impossible to drive when it does that.

I came back and left it overnight. Next morning it started right up and ran great for about 10-15 minutes and started bucking again.

I pulled the codes and got a P0300, random cylinder misfire. I also replaced the fuel filter as the stuff coming out of it was black. Once again, it started right up, idles so smooth you can't feel it, and ran great for about 20 minutes. Then the bucking started again. No codes this time.

I got a Snap-On scanner and per the device, all the sensors are working.

Thinking the fuel pump may be going bad and slinging crap into the filter which causes it to clog up after a while.. I replaced the pump and another filter. Same deal. It ran great for about 20 minutes and then the bucking started.

I have the distribuitor with the single coil in it. I've read that the coil could go bad and so can the distributor. I don't want to throw more parts at it just because.

Any ideas?

Thanks

[tonyw]

Update.

After sitting for a few days, the car started right up and idled smooth. After about 10 minutes idling, it started to run rough off idle, around 2Krpm. After another 10 minutes it started idling rough and after another 5-7, died.

The Cats get red hot when it running rough.

Whatever it is it's cumulative, it starts as a light miss or fuel starve and gets worse until the engine dies.

[smj999smj]

I had a GM 4.3L-V6 TBI in the shop the other day that was doing the same thing. Problem turned out to be a bad distributor cap. Just food for thought!