98 3RZ FE Misfire

Hello,
First issue with my new to me 98 2.7.
While driving on the highway, suddenly the CEL started flashing and the truck started msifiring, I got off the highway and retrieved a P0171, P0300, P0301 , P0304. I shut it off and waited for a few minutes, I re-started it and the misfire was gone along with the flashing CEL but I could feel that it is not running 100% but no major misfire, I drove home (about 40 miles) and as soon as I got off the exit it started misfiring again, Since I did not have time to diagnose it correctly I took a guess and ordered a coil (as it fires 1&4 , all 4 plugs and wires are new) on the initial startup after the coil replacement it was fine but then started to misfire again (P0300 , 0301, 0304) . I turned it off and waited, misfire was gone. I then parked it. Would it be fair to assume that the 1&4 cylinders are lacking fuel (lean code)? as the ignition delivery is fine and I would assume there is no mechanical fault as the misfire is intermittent

Thanks

 

Look into P0171, because the O2 sensor isn't monitoring each cylinder you could have failing injectors, or perhaps a weak fuel pump. Inspect fuel pressure first, once that is ruled out try swapping injectors around, just be sure to document which one swapped where. also when dealing with a P0171 it helps to know how lean it is, DTC sets when total FT (stft+ltft) is over 15%, is it on the lower end of that spectrum or higher. Fuel quality is another factor with P0171, I know the sticker on gas pumps say that E15, and E20 is safe for all cars, but I've seen lean codes with total fuel trims at 25% using e15 or e20, and 40-50% on Toyota's with E85 in the tank. But I'll wager in your case it's just a bad injector or 2.