check engine light
 

bought 99 runner about a month ago..everything has been fine until now...we were going through the mountains and the check engine light came on and the engine started shuttering...its the first rain i have drove trough but suspect that doesnt matter...tm is thanksgiving so its going to have to wait to be checked out..from what ive read it could be o2 sensor, maf,the afm... any suggestions would be great? does autozone still do free code checks?thanks in advance

First thing to check would be the plug wires and cap. Common to act up if they get wet and are leaking.
Robert

it finally stoped raining.so the plan is to do a tune up.spark plugs,wires,coil,air filter,clean the maf sensor...anything else i should do?...i have 3 days before i go back to work and would like to fix the problem before having to commute...i went to an autozone said they stopped doing free code checks...at the moment i cant afford to take it in, but to do the work myself..thank you for the fast response...

engine light
 

today i replaced the plugs with ngk plat g power,new air filter and tm, fuel filter...cleaned the map sensor electrodes...reset computer...engine light is off for now...well see what happens...

a possible idea is that it was sucking up to much moist air.. i dont know thats all i can think of.

hopefully the problem is fixed.. havent test drove yet but the idle smoothed out.. when parked..if i remember correctly the last time it acted funny. it was raining as well...is there anything i can do to prevent this from happening again? should i go ahead and do the fuel filter anyways as a preventive measure?thanks again

ran fine for a short drive,then started stutering again...tested the pcv seemed fine...im not sure where to go next?

well i did a full diagnostics scan everything was great exept the o2 sensor...
took 5 mins and pures like a kitten now..coil that i replaced was not the problem so i took it out and used that money for the o2 sensor...thanks everyone who had advice...toyotas sure are easy to work on compared to some big 3 models...next is new timing belt and water pump to ensure im on my way to 400k + miles...

not the problem after all...starting from scratch again....ran fine too work..on my way home it started shuddering again but not as bad?????????

dang dude thats fishy.... my check engine light stays on lol. i know its the o2's but it runs purdy good. has ran with the light on for bout a year or two. hahahahahahahahaha