03 325i rough idle in park. Hestitation when engine is revved and allow to return toward idle rpm and revved again. MAF was replace approx 1 year ago.

Does the problem occur when driving or only if revving the engine while in Park? If only while in Neutral or Park, that is due to the overrev limiter to prevent you from over revving the engine in a no-load situation. If this is a problem while driving, then we'll need to know what engine your Cavalier has and if there are any other symptoms (such as a rough idle, roughness at 3500 rpms and above). Also, when is the last time the spark plugs and spark plug wires were replaced? Is the Check Engine light or Service Engine Soon light illuminated?

the rpm limiter will pull back the rpm to limp mode
select low range 1st gear or if automatic select manual 1st gear That will allow higher rpm at low speed

The car does have a maf, but it is rarely the cause of rough idle. Rough idle is usually caused by vacuum leak, pvc issues, or idle air control valve. What does it do, specifically, and is the engine light on?

check the fuel pressure regulator and the map sensor vacuum hoses. as for the not revving above 4000 rpm is what the computer limits the engine to with no load on it, like in park or neutral.

could be numerous reasons. this is your best bet take it in to a mechanic and have your engine codes scanned. it is a minimal charge, some even do it for nothing it only takes 10 minutes.this will point you in the right direction.

all engines have a rev limiter in them to keep from revving the engine too high,they all cut out about 1900 to 2000rpms.

OK. Since you have had so much trouble lets check the dealer for an updated software calibration for the PCM (power train control module). Once we're sure there is no "fix" here lets talk about "lean" engine conditions. Lean means one of two things are wrong with the air fuel mixture (ideally 14.7 parts air to 1 part fuel). 1. Too much air -or- 2. Not enough fuel. If you access to a scan tool we need to look at fuel trims. With the engine warm look at this data on the scan tool. You have a "bank 1" and "bank 2" fuel trim data. Additionally, each bank has a long term and a short term value. With the Engine hot and at idle add the LT and ST trim value for bank1 and write it down...do the same for bank2. Repeat this step, for EACH bank with engine at 2500 RPM in park (hold at 2500 for at least 30 seconds so trims update). Now, you have the total trim values for each bank at idle and at 2500 RPM. What should the values be? Total trim +/- 5 is good, +/- 10 borderline any thing greater is code setting territory. If trim numbers are high at idle and in range at 2500 rpm you have a vacum leak behind the mass air flow sensor. Or a faulty MAF. Pay particular attention to the air inlet hose clamps behind (between MAF and engine) the MAF. Also use ford parts only.

you only set base timing to 15 degrees BTDC (before top dead center).

Ignition Timing

1. CAUTION: Parking brake control should be applied.
   Depress the parking brake pedal, and warm the engine to the normal operating temperature.

1. Turn off all electrical loads.

1. Rev the engine to 2000-3000 rpm two or three times and allow the engine to return to the idle.

1. Turn off the engine and disconnect the throttle position sensor electrical connector. (not really necessary)

1. Start the engine and rev it to 2000-3000 rpm two or three times and allow the engine to return to the idle.

1. Check the idle speed. The idle speed should be between 700-800 rpm in PARK (P) or NEUTRAL (N) position.

1. NOTE: Make sure that the timing pointer is pointing to the 15° Before Top Dead Center (BTDC) mark on the crankshaft pulley. Each notch on the crankshaft pulley represents 5 degrees.
   Check the ignition timing with a timing light.

go here for villager help

http://autos.groups.yahoo.com/group/villagerquest/

You should check your engine's AIR hoses that are connecting to the airbox. sometimes a simple airleak will be enough to alter your idle. Specially when its cold the car will already idle rough ( I know im canadian lol). So go check your air hoses ;)

I'm sure you have installed a fuel pressure gauge and monitored the fuel pressure while the problem is occurring?Another diagnostic tool which is easy to do,is while the problem is occurring,unplug one sensor at a time beginning with the Mass Air Flow first,.if it uses one.Many times,not always,depending on the sensor,if the sensor is taken out of the picture as far as what the PCM is seeing,like unplugging the MAF,the PCM will substitute the missing sensor output with a generic value that will allow the engine to at least run,and if unplugging for example the MAF,the engine idle speed returns to normal,you know you're onto the problem.You didn't mention if the engine ran ok other than the idle problem.As far as checking for vacuum leaks,i use something like brake cleaner or WD 40,more of a liquid,and it does sound like a vacuum leak.Plastic intake manifolds do develop nearly invisible cracks that open up more with heat.Revsisit the possibility.And as for the PCM,it is possible,but more likely a mechanical problem.Lastly,remove an O2 sensor or two before the catalytic convertor,run the engine and see if anything changes.Cheap way to verify the catalytic convertor is flowing and not restricting engine airflow,as i have seen bad cats cause misfire codes and strange problems.Good luck.