I drive a 2001 sun fire with the 2200 (ln2), and lately i have noticed that every time i drive the car it feels different. Some days it feels like its pulling with awesome power, and other days it feels like i only got 3 cylinders. I recently installed new plugs, wires, fuel filter, and the car has a fresh oil change. what could passably causing the varying power?

Don't hold me to this, but from personal experience. Some days the car just seems to run better then normal, and other's, not well at all.

After a plugs i never noticed any difference.
After every oil change the engine seems to have a little easier time with everything.
After changing my dryflow airfilter I noticed no difference.

Other thing's might have an effect on it too, not 100% sure. How you pre-warm you car on cold days? If you've had a long trip the day before? Type of gas from different stations? Older gas vs newer gas?

well usually the car idles about 5 min before i move it, and i always go to the same gas station, and buy the same octane level of gas. also the farthest i go is work ( about a 5-10 min drive) or just around my small town. one more thing to add, the weather here is any where from 0-15 c.

Oh sorry if it came off like I was asking you questions I'm just saying all those thing's might affect your car in different ways, can't really say for sure though.

Oh and I heard from a friend that it's best to switch up different gas stations time to time. Something about a mix of detergents being better.

yea i would say the temp. would have allot to do with it. with a drop in temp you can gain a little get up and go





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my car is loving the cold weather. ive notcied a difference since the weather has cooled. btw, i drive a 2000 sunfire with the 2200

My car seems to respond much better when its colder out (After its up to temperature that is).

Then again, it could always just be in our heads. =) Butt dynos are very accurate.... yeah.

Nothing effects the way a car runs like the way the weather is. Lord knows my friend's '87 GN ran far better on cool, damp nights than it would on a warm, dry day.


Go beyond the "bolt-on".

Ya I know what ya mean about the cold weather having a huge affect on the performance of a car, but i got a question that may sound kinda silly. Every time I add something performance related it seams like it makes a difference, but usually not for long. Is this just my mind or does these cars have a drive cycle in which they will reprogram the computer after X amount of miles, or after X amounts of starts? I know several cars i have worked on has a drive cycle in which the car automatically reprograms its self but i never really gave it much thought when it came to the j body's.

I don't know about the reprogramming, but I know I get used to how my car drives.

When I first drove my 2003 Cavalier after driving a 00 Z24 Convertible for over a year, it felt very quick.
It doesn't nearly feel as fast as it did back when, even though I've added some performance mods.

Zenith: You're going through what the friend of mine that had the GN did with every car he had... He got used to it. It's no slower or less powerful than before, it's just you having grown accustomed to it's manners. That's all.

Kevin: There is a sort of reprograming the computer does, and it called Maintainal Upkeep. Part of the ECM's memory system is the KAM ("Keep Alive" Memory). What this does is keep a continuous update as to changes made to the fine-tuning of the management's outputs in compensation for engine wear & etc. It's kept active by continuous voltage fed to it from the battery, even when the ignition is switched off.

When the battery is disconnected (for about 15min, according to some manuals), this memory is wiped clean & the ECM must learn to readjust these fine-points during the operation of the vehicle after the battery is reconnected. This doesn't take long... It'll do it within the first few miles of driving. But to be safe, it's best to put the vehicle in question through a full driving loop (On surface streets & the highway) so as to avoid hiccups surprising you. Or, better still, when disconnecting the battery (If you're changing it) plug a memory-saver into the cigarette lighter socket. This is a simple lighter-socket plug that a 9v battery plugs into. You can get it at any auto-parts store, and it'll save alotta headaches.


Go beyond the "bolt-on".

wow, thats some interesting stuff. Thanks for the info!