Hesitation

My 96 Aurora is causing me some frustration. Currently, the car really hesitates and sputters. The further down I press the accelerator, the worse the conditon gets. It starts to backfire and die the further down I press the accelerator. Up until this morning the car would start no problem and would idle well. However, the car would begin to act as described above as soon as I pushed on the accelerator. As of this morning, it will start but will die if left to idle. The 'Check Engine' light is not coming on (I know that it works since it does come on when the ignition key is initially inserted). My plugs and wires were changed about 4 years ago with AC Delco parts. The problem has cleared up in the past (in the last couple of weeks) by revving the engine a bit. We don't have any places that will read any codes for free, so any diagnosis will cost me. Could the plugs and wires need to be replaced? Or could it be something else?

Thanks.

If the plugs and wires have more than 75,000 miles then yes, install new and probably a fuel filter too.

Next possible:

Contaminated fuel maybe?

The fuel pressure regulator is a common issue but I have not heard of it causing this severe a problem.

A clogged Cat converter can cause what your describing but makes the car almost undrivable because of a complete lack of power although it will run smooth.

Does it blow black smoke when you rev the motor or does it seem to be starving for fuel?
Plugs should not cause such a drastic change in running.

[QUOTE=MTrachy]My 96 Aurora is causing me some frustration. Currently, the car really hesitates and sputters. The further down I press the accelerator, the worse the conditon gets. It starts to backfire and die the further down I press the accelerator. Up until this morning the car would start no problem and would idle well. However, the car would begin to act as described above as soon as I pushed on the accelerator. As of this morning, it will start but will die if left to idle. The 'Check Engine' light is not coming on (I know that it works since it does come on when the ignition key is initially inserted). My plugs and wires were changed about 4 years ago with AC Delco parts. The problem has cleared up in the past (in the last couple of weeks) by revving the engine a bit. We don't have any places that will read any codes for free, so any diagnosis will cost me. Could the plugs and wires need to be replaced? Or could it be something else?

Thanks.[/ a sticking egr valve can cause these symptoms.

Sticky EGR valves are notorious for causing a rough idle/stall condition but should not noticably effect acceleration if stuck open or closed except for the first few hundred RPMs. They are supposed to be closed at idle only and when stuck open they allow exhaust gasses into the intake, thus "contaminating" the fuel/air mixture causing rough idle.

I learned a valuable lesson on this one. While searching for possible causes for the hesitation, I came across the procedure for 'Idle Learn'. When I got home I tried the procedure, and lo and behold the car ran much better. For the past couple of months, I have experienced some problems with my Aurora. It started with the multifunction switch which I successfully cleaned using the procedures outlined in a post on this forum. However, the malfunctioning switch killed my battery. I replaced the battery last week. I thought that like other cars that I have owned, the computer re-teaches itself while you are driving the car. Not so with Aurora. I took the car to a mechanic just in case this was a coincidence and he spent significant time diagnosing it, but everything was fine. When I told him about the dead battery and that I had just performed the Learn Idle procedure he was certain that that had been what the problem was. It has been a couple of days now and the hesitaton is gone, and the car runs well. Put this one down to lessons learned.

P.S. the mechanic wasn't going to charge me anything but I gave him $20.00 anyways.

MT