I get a rought idle sometimes on startup and at lights once in a while. I do not have any lights or codes in the system showing, but would changing the coils help? I checked the coils and 3 out of 6 cars are different brands, not oem.... Thanks!

 

Looks like you've found your problem, I'd change them for oem as soon as, a misfire will be damaging your cats.

 

thanks for that info, even tho I do not have any check engine light on or any codes stored that I still have a misfire?

 

You can have quite a severe misfire with no codes or light.

I had such a bad misfire my engine light used to flash when the revs got above 3k, indicating cat damage, but had no codes.

The problem was water in the coil/plug Wells, causing terrible misfire.

You can buy a cop (coil on plug) tester for about $80 on fleabay

 

My 2001 4L had an annoying misfire and no codes. Replacing all 4 coils on one bank fixed it. If it hadn't fixed it, I'd have tried the new coils on the other bank!