2004 Aveo Hesitation

I have a 2004 Aveo sedan. The engine started hesitating and bucking very bad 2 months ago. I read many threads and decided to change the platinum plugs I put in, back to the copper core OEM type. I also have added Marvel Mystery oil to the crankcase and Techtron to the gasoline to try to clean the valves. There was a serpentine tensioner that was bad and that has also been repaired. While it is much better, unfortunately I am still getting hesitation from a stop to initial acceleration. At speed it is fine. It is more pronounced with the A/C (load) on. My mechanic quoted $1000 for a valve job. Besides doing a complete valve job any suggestions? 80,000 on the odometer. Thanks JR

$1000 for a valve job!!!! :O RUN AWAY FROM HIM

The valves may not have anything wrong with them. A couple of questions though, has the timing belt been done yet? How long have you owned it (mileage wise). Auto or stick?

check the coil pack and wires?

+1, like in the other threads :D

I bought the car with 70,000 miles. There is a white marker on the timing belt cover stating belt and water pump changed at 62,000. It has about 80,000 now. I have had the car for 10 months. It always ran smooth. I changed the plugs to platinum when I bought it. a month ago it started to hesitate. Now per many posts I switched back to copper core plugs. The coil pack and plugs were not changed. The car runs near perfect w/o the AC. No hesitation. When I add the AC it hesitates intermittently and sometimes during acceleration from a stop light. (Load?) Thanks...JR

Forgot to mention - Sedan, automatic, remote starter, AC, no other electrical accessories.

I have the same issue, the compressor just has way to much load on it. I have the 05 Sedan Automatic.

I have filled the ac gas with a heavier type of R-22 Gas and it helped because the compressor didn't have to work as hard, but for some reason everyone with 1st Generation automatics has this issue. The only way I have been able to fix it is hold your idle higher at a stop. It wastes gas but keeps it cool :P

Another thing you may notice is that if you accelerate fairly hard you will feel that your AC quits working around 4200 RPMs or so. Not sure why that occurs but just something I noticed

now it sounds like the high idle/ac circuit. I forget which particular sensor goes with that though..

Quote:

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Originally Posted by Siege

Another thing you may notice is that if you accelerate fairly hard you will feel that your AC quits working around 4200 RPMs or so. Not sure why that occurs but just something I noticed

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The car shuts down the a/c compressor to prevent it from getting damaged at high rpm and to also give you passing power if you need it.

Mine did the same and my mazda 3 also does the same.