The past summer I took my SS down to myrtle beach for a week...well one day when I was on my way over to the outlet's down there with the women we got a down pour. The roads were so wet I was hydro planting everywhere...well, all of a sudden I started misfiring like a mother (mind you, this is when my motor was brand spanking new, the drive down was the break in period)...it was doing it so bad to the point it didnt want to acclerate until it slowly made its way up to 3k then its like I sprayed a 100 shot...well, it did this a few times, got the blinking SES light...and it stopped and didnt do it again until yesterday...

I was on my way to boston and through the mountains it was snowing and their was alot of road salt...all of a sudden it started doing it wicked bad. I pulled over and checked my plug wires to make sure they were all on (I have had them pop off before) and everything seemed good...started it up, started driving and it was doing it wicked bad again...I slowly limped it to a rest area...I took off all the plugs wires and checked to make sure no plugs came loose or anything...and nothing. Decided it was time to turn around and bring it home and all the way home, it only did it once...the rest of the way it ran nice like nothing happened...

did it this morning for a quick 5 seconds....

I took it to get it scanned and it was 2 PO300 codes (multiple misfire) and a weird P1xxx code about mechanical air/oxygen thing (dont know exactly what it was off the top of my head)...well I cleared them, and they havent came back...

I have 2 of my 02's deleted for my Off road Y pipe...I shut them off with HP tuners so they dont show up BUT what im thinking is since they are disconnected and its a open connection, is water getting on these and causing the misfire from a short out of something? Is this possible because this is the only thing I can come up with...it seems to only happen when its really wet out.

 

I'm thinking the MAF is doing wierd stuff because of the moisture in the air. Thats just my guess. My 2001 Buick Century and my buds 2000 Chevy truck both have this same problem in wet weather.

Good luck with that, Tom

 

brother im a rookie but i had the exact same thing happen and it was a blown right bank fuse "hope im saying that right" i had the same codes and put a new fuse in it and it still misfired like crazy, i bought a scanner and cleared the codes and it runs fine. i still get the ses light and it blinks sometimes but it doesnt throw any codes so im lost on that one. **** i got new coils, maf, taylor wires, 3 sets of plugs, almost put a new fuel pressure regulator in it, countless hours with a fluke meter and schematics...now i have spare parts..and i little more knowledge..just a little

 

my car does the same thing if i run through water.
not everything though???

 

Not getting water up on top of the motor or into any vacuum lines are you??

 

what kind of intake are you running? and check vacuum lines, and are you saying that the holes in the exhaust tubes where the 02 sensors go is just left open? put a bolt in them if so

 

im running the SLP lid with a K and N filter...and the bottom of the intake box is cut out...

with the o2's I mean the 2 o2's that would have been after the cats I have deleted...their just a open connector I have zip tied up. I shut the codes off for them with HO Tuners. Im only running the front o2 sensors on o2 extensions.