Misfire under hard acceleration, code P0301.

I have a '99 Tacoma, 2.4 liter with approximately 230k miles on it. The engine starts, idles, and runs fine, but bucks / stutters / hesitates intermittently under hard acceleration. It seems to occur less when the engine warms up, but the issue still persists. Last night, I pushed the engine hard and the issue occurred again. This time, the check engine light flashed a few times, then shut off. I checked the code and it gave me P0301 - misfire cylinder #1.

When the bucking first started, I replaced the plugs then added injector / fuel system cleaner to the next 3 tanks of gas. The engine runs better (of course), but the bucking still occurs. The wires have maybe 30k-40k on them and visually look fine.

Whatever you'd like to contribute would be appreciated. Thanks!

 

A lot of things can cause a misfire. You just need to narrow it down. I recommend logical troubleshooting, not firing parts at it (unless you like wasting money).
A few things to try:
move the wire from another cylinder and see if the misfire moves. if it does, then buy a new set of wires.
Do a compression test on all cylinders- they should be close (+ - 15%). if cylinder 1 is low, then you have to figure out what your mechanical issue is.

 

This morning, I checked the #1 plug and wire, and checked for any loose / cracked hoses. The plug and wire were tight, and I didn't see any issues with any of the hoses. I then took it for a drive and had NO issues whatsoever. Although it didn't feel like it, maybe the wire was actually loose which was corrected when I removed / replaced it to check the plug. Or maybe I blew something out (from the injector?) when I pushed the engine hard last night. It was the hardest I'd rev'ed it since the issue began and the only time the CIL flashed at me. I drove it straight home after that, so I didn't test it before checking everything this morning. Who knows? I'll update this thread if the issue returns.