>>>*One thing here I see over and over is a TPS problem. But once checked out and set they should work, still, I am guessing somewhere around a dozen cases of "strange stuff" that gets fixed when it is replaced are in my files.

The other interesting thing is a bored out throttle body. That point is not a restriction since the engine is only 2.4L and can only draw so much air, so all that could happen is RPM potential. Adding airflow potential certainly can help, adding too much always hurts.

*Combine a freer flowing intake with a freer flowing head/cam combo, then add a very nice 4 into one header and it all adds up to the ECU going "WTF??" at lower RPM's, unable to compensate for a velocity drop. ...Simplistic there but it can happen.

Then it is possible for the system to start "hunting" to try and find a balance, since once baselined she basically tunes herself..

There is an old saying that bigger is not always better, and when dealing with computers, just right is.....well....just right. Everything else is...just wrong.

Your description is mildly similar to some this old man has heard before except for being WAY more extreme.

Keep digging, this is getting to be worth a sticky....You could be helping a heck of a lot of folks here, including me.

*And yep! The wrong spark plugs will sure skip at different throttle settings...*EB