1992 S-15 Jimmy

This one has had me stumped for awhile now. For some reason whenever I drive through puddles, whether in fast or slow, about 30 seconds or so it starts running like crap! On the other hand if I’m driving down the freeway in the pouring rain it doesn’t act up at all. After I go through a puddle it runs like,(imagine a spark plug wire with a hole in it resting against something metal while the truck is running)…If I drive for a few minutes though it goes back to normal. Any ideas??

you say puddles,or do you mean lakes??? eng??? trans?/???

Can you remember when the you last changed the plug wires?  How many miles.  OK you likely can't remember because they are original.  It's time for new wires.  That may not fix it, but it will eliminate the most likely cause and it gets those plug wires changed, since they are likely past due.  While you are at it, I would consider changing the plugs a well. Only a little more work and money and they are likely due anyway.

I’ve gone through big and little puddles and its the same effect…

I dont think it’s water splashing up on the plug wires, cause I can creep through the puddle and it has the same effect that it has when I drive fast through puddles???

MY QUES IS WHAT ENG IS IN YOUR VEH.AND TRANS.i would agree with meehan from experience,but if your inner splash shields are missing this will soak the wires.2.8l w motor,4.3 z mtr.

starter wires corroded,and ready to break?

Starter wires???

What does that have to do with it running rough?

Brandon… here’s a simple test you can do to see if it is an ignition wire problem. Use a spray bottle and wet down the igniton wires. If it starts to run rough then you know it’s a igntion problem, plugs,wires,coils or any combination of these things.

low amp flow to the ign sys,check your diagrams,and you’ll see why,well maybe not.