I brought my 1999 Chevy blazer out mudding the other day. It ran great all day but with mud came a lot of water. On the way back home It almost felt like the cat was clogged up but I would drive and if I gave it too much gas the engine would bog down and die. I could put it back in neutral and start it back up and it would run again with minimal gas pedal usage about every 3 tries. I let it sit last night when I got it home from a tow and started it this morning it ran fine for I would say 2 minuets and I put it into drive and it started rough idling and I pushed the gas only to kill it. I took off the cap and rotor and there wasn't any water under there but the cap had white all over the silver leads (whatever you call them). I am replacing the cap and rotor tomorrow to see if that fixes it. Any other ideas? I know water can screw up a number of things but hopefully my symptoms can narrow the results a bit. I also considered the map sensor I pulled it and it smelt like fouled gas and was a little dark but not bad. Also, maybe a mass air flow sensor? Please if you have an ideas share them, It is greatly appreciated.

 

Sounds like something was affected by the water, but without any codes to point you in any particular direction, it really is a crap shoot.

Water should not affect things, but it can. When was the last time you did a full tuneup? Maybe mist down your wires with some water from a spray bottle at night and see if you have any spark jumping out of the wires with the engine running.

 

plugs, wires, cap, rotor the full tune up wasn't much more than a year ago if that long. I did notice the fact that whatever it was made my fuel pump make some strange noises when it was struggling to stay at an idle. It threw a code but I need to get it atleast in the condition to get it to autozone for a computer scan as apposed to buying a scanner myself

 

Is there a chance that you may have gotten water into your fuel tank?
Don't waste your time with places like Auto-Zone... they use a very basic hand held scan tool at best. Find a shop with a tech2 or similar scanner and pay them for an hour labor to scan the vehicle the correct way... it will save you money and time in the big picture.

 

I was thinking water in the gas could be a definite possibility. My blazer will run and idle fine in park for the first five mins but once its put into drive it wont take much to kill it.