changed water pump, now car is missing?

[swey00]

I just changed the water pump on a 04 grand caravan with the 3.3ltr motor, and now the car is missing. took it to autozone to have the codes read, and it is reading cylinder 4 misfire...

couple weeks ago i changed a water pump on a 99 cavalier, and it is having problems too: hard starting, cutting out, stuff like that...code stored in computer is cylinder 3 misfire.

any ideas?

[Madspeed]

Those Misfire code mean exactly what they are a missfire. ( I know thats not much help )

Look for vac leaks ,Like a hose you might have left off.
If the vac leak is in one runner then that will cause a single cyl missfire.
If its not a vac leak then you need to check the plug (I have no idea how but is it cracked),check the plug wire, you could do the basics and check compression in that cylinder, If it is 100 lbs or less it wont run.

I can only think you misssed a vac hose, the water pump has nothiing to do with how the engine performs (other than keeping it cool)

[Damn True]

Perhaps a ground?

[sinned]

#4 is the front cylinder on the right side of the vehicle. 3.3/3.8 are notorious for corroded wires at the coil pack boots. Might just be a coincidence. The water pump on that vehicle about the easiest one in the world to change, I can't see you doing anything to cause the misfire.

[swey00]

thats what makes no sense, i did not undo anything on either car. i just thought i was kinda weird that both had the water pump changed and now both have pretty much the same problems.

[MrQuick]

agree also check for carbon tracking at the spark plug.