surge at stop, idle fixed

i’ve had a weird surge after replacing my battery back in october. it had a bad cell and luckily i always carry a battery jumper with me and started it to drive to a napa nearby before camping out for the weekend. they didn’t have the regular size battery that fix in the tray properly but had 1 compatible battery left with the same CCA just smaller in size. every since then it started fine but always had a surge when stopped at a light for example it would drop to extremely low RPM and kinda hang on for life. no lights no codes, didn’t think anything of it. cleaned the throttle body, re learned the idle, cleaned MAF, etc. that was at 93k miles.

this past weekend i went mudding and got stuck past the frame of the truck up to the middle of my doors. truck died obviously. put the winch to use and got out. fired right up. maybe 30 mins later at idle the battery light popped on. that’s usually a dead sign of an alternator that’s fried but i thought it was because the mud that was packed inside of it. i power washed the engine bay and got rid of it all. battery light went away for a good 10 mins then came back. SHIT. I’m 40 miles from home.

i drove the 40 miles home just on the battery, FYI, turn everything OFF. ac, radio, bluetooth, lights (if light enough outside) etc.

had the alternator replaced toyota OEM,new belt and crank seal (warped and leaking everywhere)

the surge is gone! i think from 93k miles it was slowly going out and i just wasn’t paying attention. i’m now at 100k+ miles and the surge is finally gone after replacing that damn thing. hope this helps someone! it’s pretty badass that the alternator lasted 10 years, 100k miles.

TOYOTA!