Got a code tonight - P0303 - Misfire on cyl # 3.
 

I left work and started the car and it was running a little rough, stopped the engine and restarted and all was well.
I had a ck engine lite come on as soon as I restarted the engine and as soon as I got home I hooked up the scanner and got a Code.
P0303 - Misfire on cyl # 3.
I just added new plugs and wires less than 300 miles ago.


Any Ideas?

its very possible one of your wires is defective. what brand did you use??

Check wires and coil pack to begin with. Any other codes?

I don't have a whole lot of knowledge in this area, bit let me know if you want the FSMs and I will bring them down to you.

Bob

make sure the wire isn't gounding out, connections are solid, and check the plug just in case.

That is what I would start off doing.

Nick,
Follow the wire and look for any scuffs or burn marks on it. Make sure it is not resting on sharp metal.

If you have a multimeter, test the ohm reading on your three coils. They should all be reasonably close.

If both those pass then pull the plug and change it with a new one. It is possible, but not probable that it cracked and is causing the problem.

or..yeah..what the other guys said!

Good morning......

As for all the questions asked.....

Plug wires - typical wires from Autozone
Plugs - Platinum plugs

the #3 wire is the wire that looks to be twisted at the coil pack and runs under the wire guard which runs the length of the valve cover, there are no kinks under the cover but I found it was kinked just as it leaves the coil pack. I removed the kink from it but I will remove the wire on saturday to inspect it completely, have no time until then......

My 99 lesabre with the 3800 Series 2 engine did this, but mine was cylinder #1.
With the engine OFF, Pull off the wire on the coil pack for cylinder 3, and see if it delivers spark when you start the engine. You will hear it even from the cab of the car.

If it does not spark, shut off the engine, swap out That coil with one of the other two (All three coils are interchangeable), reconnect the spark wires (but make sure you connect the spark wires according to their proper position and not the numbers on the coil packs, since the numbers are now incorrect) Leave #3 position disconnected. If it sparks NOW when you start the engine, you know the coil pack is bad and not something else. If it does not spark, you have possibly other problems.
Check the connection to the coil packs for corrosion and a secure connection.

A new coil is only about $30 aftermarket.
I hope this all made sense. Kind of hard to describe without photos. If you have questions about what I just wrote, PM me and I will see what i can do.

It looks like everyone's cover the basics.

I had this happen once, right after changing the wires with off the shelf parts store wires. Car ran worse AFTER than it had before the tune up. Turns out that one of the wires was bad. Replaced them with a premium set of wires to fix it.

Good luck!

Nick..your very issue is what brought me to Bonneville Club. I had a misfire and searched the net and landed here! ;)

Anyway, the fix to my 99 was to replace the plugs and wires. I had replaced them once, but I ended up having a defect one. After I swapped them I cleared the codes and the issue never resurfaced.

thanks for all the reply's back on this issue....

I did check the wires and I pulled and reseated them at both ends and I have not had the problem since... maybe I got lucky......