I'm at a dead end. Have a 03 caravan with 3.3 that started to have a rough idle while in gear. It acts like there is a miss. When I accelerate it hesitates then goes. One time it started to backfire a little. It is throwing no codes. It also seems to be worse when there is a load on the motor, ie A/C and blower on. What I have done is changed spark plugs, wires, cleaned throttle body and AIT, new throttle position sensor, checked for fraying wires and vacuum leaks( which were none). My question is there anything to look at that won't throw a code? Thought about battery and alternator, but I would think those would throw a code. I haven't checked the battery because I need to buy a new meter. Any help is appreciated.