Mystery Car Problem

I have a 2005 Dodge Neon and after alomst three years of having this car I’m having alot of problems, but this one problem has me and my dealer stumped. The problem is that whenever I turn on my car after awhile it starts bounceing up and down and shakeing under my hood also all my lights (headlights and dashboard lights)start flickering. I’ve took it to get checked out and for some reason no one I mean no one can’t seem to know what is causing it so please if you have any suggestions let me know Thanks!!!

There is a bad imbalance in the engine. It could be from misfire in various cylinders, or some massive part of the engine is moving in a manner it shouldn’t, such as the flywheel (loose, warped), the harmonic balancer (broken rubber, loose).

You may have a bad engine control computer and maybe that’s why the stored codes make no sense. Somebody should use some diagnostic tools to find out what the codes even are.

I agree with Pleasdodgevan about the ECU possibly being the cause of this. Especially if the alternator is regulated by the ECU as some Dodge vehicles are. I would check the regulator voltage to see what is doing. There may be a component in the ECU that heats up and starts causing this problem. I suspect the engine is responding to the voltage variations which are supplied to the ECU. The easiest way to determine if the ECU is the cause would be to try swapping it with another unit.

The power flucuations could also be caused by a problem in the main accessory power buss. Possibly a faulty relay contact.

Bouncing up and down? Shaking? Lights flickering? Is this a Halloween prank? If this stumps the dealer I’d suggest an exorcist. Sounds a bit fishy to me. Rocketman