Misfire and boggs down when cold, 98 4runner v6

[Seanz0rz]

got my code reader, plugged it in, no codes whatsoever.

this is really frustrating...

this morning when i started it up, i had no problem with it at all. didnt bogg, stumble, buck, surge, anything. started up great, ran great.

i'm confused. any insight?

[paddlenbike]

I would start with the simple stuff. Clean the MAF (there's a temp sensor in there that can get dirty and throw off the calculations for the air/fuel ratio), clean up the spark plugs, clean the throttle body and if you haven't touched it, perhaps clean the idle air controller.

[Seanz0rz]

IAC and TB are clean. I will clean the MAF later today and check it and the TPS with the specs in the FSM.

[Seanz0rz]

no issues this morning either. im beginning to think maybe bad gas. ill keep monitoring it, but as far as im concerned, the truck is solid again.

[4x4mike]

Did you guys have rain around the last time you filled up? Like I mentioned above you had similar problems to a friend of mine and thought I'd throw it out there. In his case in as in a 250 shifter kart but after a race, especially if you win like he does, they test the gas to make sure they're not doping. Through that test and another he found he had wet fuel. FWIW he uses 110 octane from a sealed can.

[Seanz0rz]

i honestly cant remember if it had rained when i filled up last. i remember filling up in the rain, but not sure if that was this tank or the tank before (i fill up so often between all the vehicles, i cant remember)

it was raining the first two times it happened, and it had rained the day before it happened the third time (which wasnt as bad)

could my ECU or wiring be getting wet somehow?

[YotaFun]

I had that issue and found one of my spark plug wires wasn't connected correctly at the coil pack

[Seanz0rz]

tried again this morning (over 48 hours since it was last started, and cooler than the previous mornings)

did it a little bit, but only when under load (trans in drive or reverse, but NOT in park or neutral)

no codes, and it corrected itself quickly once the engine started getting some warmth to it

[MTL_4runner]

Pull off your coil packs and try looking for water/rust traces or carbon arcing on the boots.

[Seanz0rz]

so an update.

on thursday, 3-29, i started the truck and drove it around the block. i got it to misfire, and flash the check engine light. read the code. P0306, cyl 6 misfire.

truck ran great for the entire trip, did well on fuel (but not too well, indicating leaning out of the AFR) and no problems EXCEPT FOR:

driving through a deep water crossing, water splashed up into the engine and caused a P0300, P0304, P0306. that is random misfire, and cyl 4 and 6 misfire.

not sure if that has anything to do with my problem, but maybe moisture is getting on the wires and causing arcing back to the block instead of through the plugs.


my intended course of action:
get a spray bottle with water. start the truck and spray the wires and look for arcing back to the block under moist conditions.