You guys have helped me out a ton with other problems before, saying that, please bare with me as this will be lengthy.

A few months ago during a snowstorm in 4 wheel drive, truck started to sputter, miss, backfire and sound like its sucking a bunch of air. No power, ba Made it home, went out the next morning and didnt have an issue. Couple days later, same problem. it seems to happen only when its wet. I replaced the distributor, cap, rotor, plugs, wires, iac, and it didnt help at all. When it snowed again, i had the same problem, but got no bus in the odometer, so i put a pcm in it and it seemed to help, until it rained. then the same problem came up. I'm really at a loss. I've checked the grounds, pulled the fuse box looking for corrosion on the underside and found none, last time it happened i checked under the hood and nothing is wet. I just sprayed the plug behind the front left tire thinking maybe a wire is rubbed through and shorting out, but it ran fine. All this is happening without a single code being thrown. Short of ohm testing every wire from the pcm, im at a loss. Any help would be appreciated. Thanks in advance.

Truck is a 99 ex/sb, 4x4, 360 210k. Only mod im aware of is a cold air intake.

 

Is the weather seal at the back of the hood still in place? What about the rubber flap that goes over the PCM connectors?

I would be tempted, if none of that pans out, to set my garden hose on a 'mist' pattern, start the truck, and spray around under the hood, and see what happens.

 

is the ignition coil cracked and going bad?

 

Wait for a dark night and open the hood and see if there is any arcing somewhere.

 

The seal at the back of the hood on the cowl is there, but there isnt a cover over the plugs on the pcm. I have sprayed under the hood and up from underneath and got nothing. I have also looked under the hood when it starts messing up and nothing i can see is wet.

I sprayed the coil with water and it didnt do anything. The coil wires are butt connected together where it looks like they were cut, but have never had an issue with them.

I checked it out at night running looking for arcs and found nothing. When hooking the battery up one time i did hear an arc from somewhere but couldnt find where it came from.

I had it in the shop the other day and found the negative battery cable, where the wires go in was kinda sloppy and loose, so i put a cable end on it, and found the power wire that goes from the alternator to the fuse box had a split and was corroded a little bit, so i fixed that and waiting to see what happens. But it doesnt do it every time its wet. I drove it for about an hour and a half before it messed up the last time in the rain without a problem, just to have it mess up in the rain the next morning.

 

Seriously? Replace them!

 

I plan to grab a new connector next time I'm at the junkyard. I cant find the connector new anywhere.

 

No, no, no. Just go with new wires. Or at least one new wire.

 

Think you may need to do some data logging, while the problem is presenting itself, to find out what's going on. One would think, if it was a "wet" problem, spraying it with the hose while running would most certainly make it act up. The fact that it didn't is just bizarre.

 

When i had my scanner hooked up (snap on solus edge) it loses communication with the truck. That tells me the pcm is losing power or ground. But i couldnt tell you where.