1993 Pontiac Grand AM GT Motor Hesitation

Have had this car for 2 years now, and after a long time I finally got sick of the jerking and engine hesitation. I went out and bought a new fuel filter, and set of spark plugs, and sparkplug wires. Replace them all today May 7th, 2006. Sadly, the engine seems to be running worse than it was before. Before every time the car was stopped, you gave it gas, it would hesitate to move, then start jerking and coughing like it was having a heart attack. It would also have trouble shifting (It is a automatic), and ive put the right amount of transmission fluid in also. Now it doesn't accelerate as fast as it did before the change. Me and my father (he is a certified mechanic) checked the spark plug firing order over four times, and figured all is good with it. We warmed it all up also and tried again, same thing.

The fuel filter and spark plug wires are NAPA, and the spark plugs are ACDELCO.

Anybody have any ideas? It'd be great.

More information
1993 Pontiac Grand AM GT
White
3.3L V6

Most recent repairs was some tire problems, one of the exhaust pipes has a hole in it, replaced serpentine belt (no problems after that was installed 2 weeks ago), and an oil change. Used around 4 bottles of fuel injector cleaner in the past 2 months, and 9 in the past year.

Does it jerk and cough with it just setting in Park at idle?

Hows your fuel pressure?

I'd start with checking the spark with a spark tester to make sure your coils are working right.
If they are getting the right amount of spark, test the injectors to make sure they are 100%.

I'll PM you a link .

Yeah, when its idle it seems like its coughing, and gets louder for a sec, back down, then louder, back down. When the car was on my dad pulled the plugs off and watched how the plugs where functioning and said it was all good because each plug looked how it should I guess. We haven't tested the injectors or fuel pressure either.

What would explain the coughing and jerking during the shifting though? And on takeoff?

I don't know much about the V6's, but if they have an idle control motor on the thoratle body (like the quad 4's have), you might want to clean the carbon off that (not twisting it, and clean the cavity. Your symptoms sound alot like a that of a dirty idle control motor. Other things to check would be the fuel pressure regulator on the fuel rail (sometime they leak out the vacume line). Also look at the thoratle body to make sure its not dirty & not closing properly, cheking the fuel pressure isn't a bad thing, & checking for spark is pretty easy, doing these few things should help you determine the cause.

.... and gets louder for a sec, back down, then louder, back down. ...

Hi, if this problem happen only when on Park (not on neutral), i know what your problem is, my car has the same. When the car is on park, the orange light next to to P on the transmission shut off, then the RPM goes down to 500rpm, then going up to 1000rpm, and so on. it may last a couple of minute. when the light goes on again, the problem stop, idling 500rpm, you may press the light (when it's off) and then the light come on again and the car idling correctly.

It's a common problem to the 3300 GM, if you want more info, just post back.

I hope it's solve a part of your problem.

test your MAF. My 93 went through a couple of them and it done this up and down idle.

I put my car in the shop, and they found out that the vacumn intake was leaking, and not getting to the sensor to bring gas in. It was getting too much air, and not enough gas. The other problem was that two coils were really weak, and needed to be fixed. The total came to like $308 in fixes.