So on the way home from work just now my truck started to run bad and the check engine light was flashing so I stopped at a gas station to see what's going on ...the only thing I can think of is a wire is getting wet and the on wire up top that is getting wet is the wire to the MAP sensor ...so hopefully tomorrow it drys up under my hood so I can drive my truck and track down the fucked up wire ...the truck was running good before I started to drive it in the rain... Let me know what y'all think ....Thanks ...02 Silverado with H/C LQ9 swap

 

ses light still on? pull the codes. if i recall, a flashing ses is a misfire. so i doubt your map sensor will be the issue.

 

/give up and take it in lol if its a wiring issue.

 

Yes, flashing is a misfire. Hook a scanner up and see what codes it is throwing, it could be certain cyl. or a random misfire.

 

I changed the plug wires and put heat in my gas and it's running good right now so we will see ....

 

scan the codes...
go to any parts store, they'll do it for free!
flashing SES is Cat failure imminent, aka misfires