I got my coils checked at Midas and the local dealer and both places said they're fine. They also said no codes came up for the knock sensor when I asked about it. What else could be causing the "bump" I feel while idling?

 

try cleaning the tb....coils are really really hard to detect unless you get a code, even checking with an ohmmeter is unreliable. the coil values may read okay with the engine off , but under load and heat, etc. they are bad.

 

Testing coils packs with an ohm meter is not reliable. I've have 6 paacks which will test fine either hot/cold but place them in the car under load conditions and they will misfire.

One way to trigger a coil pack code is to drive the car rough. From start, floor it, get up some speed, slow down quickly, floor it again, etc. Many times this will trigger the misfire code.

If your coil packs are ok, maybe fuel injector problem. There easy to test, see Haynes manual. May also want to run some TECHRON through car and see if that helps.

 

UPDATE:

The dealer said it could be AAC Valve. Anybody know anything about this? Cost to install at a mechanic, etc? They charged me $125 just to tell me this and give me a free key ring!

 

I used to feel a "bump" while at idle. My problem disappeared after changing the fuel filter and PCV valve.