jerichardson3

So i have a 2002 V6 3.8L mustang with 110k on it. I had taken it to the dealer becuase of hesitation and skipping and they reported a misfire and installed a coil pack. I have no mods to the engine but I am having problems with the car now especially when it rains. After about 20 mins of driving in the rain the car will idle rough. I can be stopped at a light and the RPMs will drop from a normal 800 down to 200 and the car will start vibrating and shaking. It will stay low for about 10 seconds then shoot back up to 1,000. Always happens in the rain. I took it back to the dealer and they reported no problems on any cynlinders. The car i believe misfires slightly at all times as the car seems jumpy but you can only notice it as the driver. The car also has a problem with accelerating in 2nd gear getting stuck at 2,000 RPMS and not moving faster but i can hear the engine going until the car shifts to third. It was suggested that i get new spark plugs and clean the Idle Air Control part and see what that does. I am curious to know why it always acts up in the rain? Anyone have any advice as to what i should replace like the spark plugs? I have no idea when they were last changed

Old Mustanger

Sounds like spark plug wires to me.
In high humidity conditions they can arc through the insulation & the spark doesn't always reach the plugs.
Good luck.

jerichardson3

Ok I'll change those out. Know where I can find out how to do it on my car?

NeoTokyo

Plug wires or coil pack.

If your coil pack has a crack in it high moisture will cause it to missfire, I had the same problem on my old 01'.

Try to stick with Motorcraft but the Borg Warner was the one I bought because it has a lifetime warranty, it worked great.

Old Mustanger

For plug wires, you just change one wire at a time so you can't make any mistakes. I usually remove the shortest wire first and replace it with the shortest new wire. Then go to the next shortest wire. As long as you only remove one wire at a time you can't really make mistakes. Make certain that the metal end of the wire is securely clicked into the coil pack then do the same on the plug end.
Don't buy the cheapest wires you can find, buy a good brand.

Changing plug wires is easy and you will save a LOT of cash. Take your time, wipe everything clean and ONLY remove ONE wire at a time!
Good luck.

jerichardson3

Ok so today i replaced all the spark plugs and spark plug wires with new motorcraft wires and plugs. It seems to be running a little easier but im still noticing a little hesitation and jerking. Its only noticable to the driver though. It hasnt rained yet so im eager to see what will happen when it does to see if this fixed it. I will post when the car has been through the rain.