96 grand am hesitation problem

Hi guys i dont even know where to start but i will give it my best try.
Around december 2004 i started having a big hesitation problem with my 96 3.1L grand am. I started with a turn up replacing spark plugs and wires fuel filter and air filter and no luck. So i talked with many ppl and had been reading about similar problems on the net so next i replaced my throtle positioning sensor and cleaned my IAC sensor and throtle body even though my car idles like a champ. Also replaced my ETS (engine temp sensor)-Coolant temp sensor and with all of those no luck either. So next i was thinking my cat and fuel pump so i went and had my fuel pressure tested and it tested good around 40-44 psi and also checked cat and checked out alright. So next i was thinking ingnition control moduel (ICM) so i replaced that and also bought new coil packs, big mistake waste of money still no luck. So im still stumped i have no idea what so ever what could cause this, i have seriouly put some thought into selling the car because of this and i havent had it a year yet. it has 94,000 miles on it. So any ideas or help what so ever would be greatly appriciated thanks.

ohh yeah just wanted to add that there has been no check engine light come on what so ever, and it does work.

When does the car hesitate? During acceleration or during deceleration? You may have a Crank Position Sensor going bad. Since they control when the spark is fired this may not be properly sending a signal to the computer. I would replace it since you have replaced about everything else.

its during acceleration, i think you call it hesitating but i just know that it has no power and the rpms dont harly even climb untill the pedel is almost on the floor they shoot up really fast and even then u can still fill its not running right. I was talking to my dad today and he wants me to drop my gas tank this weekend and clean the fuel pump screen because when we changed the fuel filter he said it was the dirtest filter he has ever seen. But honestly i dont think its that screen.

I would agree. I don't think its the screen either. I am having the same problem with my 94, same engine. I replaced the fuel filters, fuel pump, the ICM, and an EGR valve still not fixed. The check engine light comes on every once in awhile but can never catch it on to do a check. But I'm gonna try to replace the crank position sensor like GTP dad said. If you do it before I do let us know how it goes, if I get to it before you do I'll pass on the results.

Well just eliminated yet another possiblilty today. I droped the tank and replaced the screen and cleaned up the tank alittle and it didnt look to dirty and didn't fix it either so i am thinking i will be replacing th crank positioning sensor soon. I was also talking to some of my buddys at work who are mechanics and they say it could be the timming chain too but i would think the car wouldnt hardly run if it was that. So if anyone has anymore thoughts to what this problem is let me know.

Well if the mechanics said it might be the timing chain i think i would be finding some new mechanics.

Well i had my cars fuel pressure checked again today and its 40 at idle and like 44 45psi when you rev it, i have been hearing that that is possibly to low so i called the delear today and asked them and they said it should be around 60psi so im thinking thats my problem, but i was also told to look at the fuel pressure regulator since the pump is working when you rev the motor up.

Have you had you O2 sensor checked... I had the same type of acceleration problem where as you accelerate you lose engine power and then it kicks in. My code finally went off and it ended up being the O2 sensor and the O2 ground.

well i have yet another failed update i replaced the fuel pump today and yet again i still have the same old problem, my dad wants me to do my fuel injectors and go have them all rebuild and flow tested but thats like another 120 bucks to go blow if its still not going to fix the problem, i havent had my o2 sensors checked, my engine light has came on a few times saying faulty reading by the o2 sensor i have been just kinda blowing that off figureing there is no way that an o2 sensor could cause such a power loss problem like that but maybe i better be looking in to that also.

I don't mean to say I told you so but I did. You asked for advice and people are giving it to you but you seem to be ignoring what the folks here are saying and wasting your money. You have focused on the fuel side of the system but your problem lies on the ignition side. If you haven't changed plugs and wires you may want to do that as well as changing the CPS.

I agree with you GTP Dad. I told you it wasn't the fuel pump. That was a waste of money. I just replaced the CPS today and guess what. Fixed the prob. Runs great. You need to look into it. I would bet money on it that it is ths CPS.

Another possibility that wasn't mentioned could be dirty / clogged fuel injector(s). If they are the culprit, a fuel injector purge (roughly 80 $ at a shop) would make a huge difference.

Hey Evan well i have my intake all taken apart so i can have my fuel injectors professonally cleaned
(Flow Bench with the Industrial Strength Ultrasonic Clean to flow test, ultrasonically clean, and recondition
fuel injectors.)but while im at that i will
be doing the CPS also was it very hard to do, i am not sure where its located either.
Also another question did your car idle good and everything. because mine idle's great and
revs fine and only runs bad when under load.
My car runs great except when I enguage it in gear. Revs fine unti loaded then she boggs .