2007 XLT Idling rough

[Mackj5]

I have a 2007 XLT with approximately 94k miles. It has had the check engine light on for a while throwing the code for catalytic converters. I could not swing the insane price at the time and it was running fine. I spent the money on new plugs because I had been told that it is possible for plugs and/or O2 sensors to throw the same code. The check engine light went out after changing the plugs. It has come on and off a few times since. I drive it to the store today and it ran fine. I left it running while in the store and when I came out to leave it was running quite rough at an idle. Rough enough to shake the vehicle. As I drive off and it gained rpms it seemed to clear up. Stopping at the lights and idling it would go back to running rough. Any of you gear heads know if this is definitely the catalytic converters needing changed? If so, any tips on how to not spend $2000 on getting it done?! Any help would be appreciated! Thank you!

 

[bedrck46]

kindly post what the code numbers were
also when you changed the plugs did you install new coils or at least replace the boots

 

[Mackj5]

I'm sorry I do not have the code numbers. I was only told it was the cats by two different people. I only changed the plugs.

 

[Jdm5630]

Did you replace the coil packs when you changed the plugs?

 

[Mackj5]

No I did not. I only replaced the plugs.

 

[bedrck46]

Take the expy to advanced auto and have the codes read, then post the codes here on the forum.

 

[Mackj5]

Will do! Thanks

 

[jkrake]

More than likely it's a coil pack.
Probably #4

 

[bedrck46]

More than likely it's a coil pack.
Probably #4

without knowing the codes, saying it a coil pack is just a guess.
might be a good guess but still a guess.

I say that because I had a problem of a misfire on # 4 one time and was told it was either the plug or coil pac problem turned out to be a pinhole in the boot

 

[Jdm5630]

I would replace all coil packs

 

[jkrake]

I bought a complete set of coil packs for my 98 expy for under $100 on amazon.
No problems since.

 

[bedrck46]

I bought a complete set of coil packs for my 98 expy for under $100 on amazon.
No problems since.

what caused you to replace the coil pacs was it just a guess or were you having mis-fire problems
did you have a cel and get the codes read
or were you just doing maintenance and replacing plugs and cop's

 

[jkrake]

I had an issue with it a couple years ago and the codes read misfire on #4 so I bought a new coil pack and that fixed it.
Earlier this spring I started having problems again and just decided to change them all out which I read somewhere was suggested. Plugged catalytic converters can cause it to run rough also and if not fixed can start causing other issues like blowing a manifold gasket.