might have to sell 06 Aveo. Running rough. 85k mi.

[rrb6699]

I may be selling mine soon. I'll tell you it does have a problem. It runs fine then runs rough. New Heads new belt timing belt new water pump new sensors. I'm going to test the catalytic converter and if it is not the problem and it still runs rough I'm selling the Aveo. Only 85000 miles. I'm giving it one more chance. I can't keep throwing $ at a problem nobody can diagnose (shops, etc) any better than I can. spending too much time on a car I should just be able to get in and drive.

It acts up once it get to operating temp. engine starts with no issues. runs fine then I hear what sounds like a small bearing noise after several minutes. once it gets to operating temp, the engine starts shaking/ vibrating, there's no power, etc. check engine light comes on and flashes.

a friend resets it, wait for the engine to cool down and we're back to square one. I replaced the water pump that had a leak, all the head and exhaust seals, timing belt, coil pack, plug wires and battery.

I figure either the Cat is heating up, causing backpressure, heat, then things start goin south or there's a roller bering that gets hot, starts seizing or causing resistance on the timing belt - one of the smooth rollers imo.

how do I test the Cat and can I do something meantime to both ease backpressure and trick the o2 sensor so I can drive it further than 5 miles? what tools? where do I hook them up? etc... methods to for sure nail this down.

the gaskets on top, intake, valve cover are also new.

when I turn the car off there is a hiss then it stops.

I'm goin to pull the front timing cover and listen to each pulley and roller/waterpump. could a roller bearing cause this issue making the computer try to compensate then throw things off?

let me know.

[Bluemoon]

this might be off base big time but at one time i owned a Saturn that was doing about the same thing, after replacing a crap load of thing into it, it ended up being the computer failing and sending wrong signals to the rest of the car.

[MarkNelsonMovies]

The first thing I would check is the PCV system, make sure all the hoses are good etc...
A hissing seems to indicate pressure building up somewhere, if it's air it would have to be the intake (check the hoses and what not), the crankcase ventilation (PCV), or the exhaust (you've got the right idea there, but I'm not a mechanic so I don't know how you would test it.)