Misfire and Hesitation

I have a 97 with 88K and it just started misfiring and hesitating under acceleration and normal driving. I hoped it was bad gas but ran all of it out, put fresh 93 octane in with treatment and it's no better.
It also backfires - you can here it under the hood when driving more than you can out of the exhaust.
I know that it could probably be some sensor, plugs, plug wires, coolant in one of the cylinders, etc. but I was hoping that maybe someone else has had the same problem and can save me some time and money by knowing what the most likely problem is.
If not, does any one know if having the diagnostics ran on it will pin point the problem or not?
Thanks for your help...

Sounds like plugs and maybe wires. When were they last replaced? If you have the originals then it's time to change them.

Sounds like plugs and maybe wires. When were they last replaced? If you have the originals then it's time to change them.
They are the original plugs and wires but I thought that the plugs were supposed to be good for over 100K?

The operative word there is "supposed".
My Olds dealer says that plugs and wires probably last for 50 to 60 thousand miles - more than that you're doing better than average.
I had the same problem - misfiring, poor acceleration, backfiring etc, New plugs and wires solved the problem, it was like getting a new car.

The operative word there is "supposed".
My Olds dealer says that plugs and wires probably last for 50 to 60 thousand miles - more than that you're doing better than average.
I had the same problem - misfiring, poor acceleration, backfiring etc, New plugs and wires solved the problem, it was like getting a new car.

Thanks for the feedback dred.
One more question - I found plug wires from $75 to $150 per set. Do you think it's really worth the extra bucks for the higher priced ones? Which ones did you you replace yours with?

I had mine done by a Cadillac/Olds dealer - they put in AC Delco plugs and wires. Aurora's are fussy about these things - it's best to stick with the recommended AC Delco.

i put new wires on last week and as dred98 mentioned it truly is like getting a new car,terrific gas mileage, no more rough idle at red lites, the tach is smooth at 800 rmp,a long overdue investment and worth every cent,they are expensive for a tailor fit set,dont settle for less...news

A dirty/stuck EGR valve can cause smilar symptoms also. Does it run very rich? Black smoke from the exhuast? It's one of those things that happens all of a sudden. Runs ok, start it up and runs like crap.
Easy enough to clean so you can eliminate that as the problem.

A dirty/stuck EGR valve can cause smilar symptoms also. Does it run very rich? Black smoke from the exhuast? It's one of those things that happens all of a sudden. Runs ok, start it up and runs like crap.
Easy enough to clean so you can eliminate that as the problem.

It hasn't been smoking. It did kind of start al of sudden though and is steadily getting worse.
A new EGR valve is about $140.
Where is it located? I will probably clean it just to be sure.

Plugs And Wires Fixed Mine At 55,000. The Wires Were Shorting Out Against The Valve Covers, And The Plugs Looked Burnt. Put Accel 8mm Wires And Bosch +4 Plugs In. Ran Like A New Car After That.

AFTER replacing plugs and wires and it still does it look at coils. I had mine scanned to pinpoint the exact coil. Replace 1 at a time. Also 100,000 mileage doesn't mention years, yours and mine are 7 years old. To a car thats painful.

I still don't understand why some one would think putting a cage around the spark would make it better. A plug only makes one arc at a time. Split fires were all the rage a few years ago now manufactures are selling plugs with four electrodes. Craziness.
Ac Delco parts will serve you well. They were designed to work with the system.