I have a 2000 Cavalier Z24 with the 2.4 liter DOHC engine. Recenty it runs like it has no power at all, have a hard time getting the car past 100km/h. It runs smooth enough but no power. I had the car checked and catalytic converter replaced. Car has a little more power but still gutless. Is it possible the timing could be off slightyly. I know is a chain drive and a big job to do on this model of car. If I take it to GM, can they tell right away on their diagnostic equipment?

Hello Skoda

The only thing I can suggest for you, is, you say it runs smooth.

If timing was out you do normally hear it as the engine will sound rough

I am also sure you can appreciate without hearing the engine it is very difficult to judge

But, underpower can be caused by :

Not enough fuel being injected
Lack of compression
Lack of oxygen causing a low igntion
Low spark rate from either worn leads or old spark plugs

Timing could be out but general rule is, if the timing is out the pistons meet the values and game over

You need it to be checked bya trained mechanic to find the cause

Phlanx

Thanks phlanx,

The car had the injectors changed, checked for vacuum leaks, compression was tested and found to be around 170 pounds and also new spark plugs. Not too familiar with the diagnostic equipment GM uses and if they could pinpoint if it were the timing right away

By the sound you have checked everything you can without the computer

It could be the main ECU has either gone wrong and not timing the injectors correctly, or the ECU has gone into safety mode where an engine speed can be limited until the problem can be fixed and therefore protects the engine (Engine management light should have come up, but the bulb could always be broken)

Eitherway, if the mechanics of the engine are working fine, then it does sound like a Diagnostic on the ECU is needed

. Replace platinum spark plugs (ACDelco only), if they have over 50,000 miles on them.

. Replace the Ignition Control Module (ICM) and coil.

I recommend replacing the ICM and coil every 120,000 miles or 10 years, whichever comes first.

Got the car back from GM today. Turned out to be the coil pack and spring assembly. Mechanic told me whoever rebuilt the engine must have had the wires pinched when they were reassembling and over time they wore and melted this coil housing which prevented all 4 coils and springs from being held in proper position. I hope that makes sense to you all as I am not a mechanic just trying to relay back what I was told. Anyway car runs great now. Thank for all the advice.