Haven't contributed here but am willing to help when I can. Need any marine electronic advice. I'm your guy but heres my plea for help!

98 Expy 4.6W on the way home (1 hour into 4 hr drive) started running poorly. CEL began blinking the steady then blinking. Pulled into AZ and got scanner. Codes were P0303, P0171 & P0174.
Did my research and found the crack in pvc fitting behind intake man. Pulled #3 plug boot and found the boot to be wet which appeared to be rusty water. Checked oil (changed a week ago) No water found in oil. However Res tank appears a bit low. Pulled plug appeared norm maybe a lil black from no fire I've read where hose leaks and maybe even head gaskets can cause this. Would a blown gasket cause water to collect around the plug boot?
Give me your thoughts

 

Check the hoses above #3 heater hose leaks down into #3 & 4.

 

I did take a look at those hose with the funky fittings on the end. They seem intact, but from what I've seen there's been a lot issues with those

 

Coolant comes from the opposite end of those hoses with funcky fittings lol.

Yea, it doesn't happen all the time, - only when conditions are met. It's a high pressure burst. You have a leak.

 

that and brew, thanks for your suggestions. I will check them if not replace

 

Yea, checkout what jethat and I suggested. There's not much else it could be.

 

blow out the hole and keep going, the water is prob rusty cause it's been there since you last washed the engine. Di-electric the coil pack on re-install.
CEL??? you mean MIL maybe?
don't think coolant can get in there any other way than driping in from above so head gasket is out of question.

 

Yes it can, that was half explained.

 

Yup i had the same exact problem with my truck, the heater core hose only cost me 17$ from advanced auto so not too bad. replacing it is not too bad either unless the dam fitting at the heater core doesnt want to come off, which happened to me, the plastic that you push in to get it off was jamed full of dirt, so what i did was use a dremel to cut the plastic locks off, which then it came off great and it snapped on and no problems since, just make sure you have to hose all the way down the tube on the intake also.

 

First off thanks to all you have taken the time to help out. I have yet to find the leaking hose but I plan on checking it out more intensely Fri morn while off from work. I did however notice a strange "trickling sound" from under the dash today on the way home. Damm lil Gremlins.