I have an 04 cav with 178000 miles. It will miss or jerk during acceleration and while maintaining speed. It will also sometimes die when slowing down to stop. The tach juumps up and down during. I have already replaced the plugs, fuel filter, fuel pump, cap with coil packs, boots and module, and tried injector cleaner. The check engine light never comes on. Any help would be appreciated. Thanks.

What kind of transmission doesn't it have, an 4 speed automatic? I'm not sure what year was the last for the 3 speed. Actually it would help if you listed your powertrain. This sounds like it could be an AT problem, the lockup torque converter or the transmission itself going out . Probably want to check the fluid level and drain and change the filter if you haven't already. It's long over due.

trans is auto, 2.2 ecotec, not sure on the powertrain

trans is auto, 2.2 ecotec, not sure on the powertrain

It's probably the 4t40 4 speed. If you have over-drive and no trans dipstick that would be it.