Here's a new one for me; all of a sudden my 95 started acting like it is running out of gas. Bounces a bit at idle, low speed take-off starts with an initial miss, then some mild surging. Does it pretty much up to freeway speeds then when you settle down at say 65, you can't really notice it. Does not feel like a blunt electronic-like miss, its a softer, fluid-like surge like just before you run out of gas.
Before this started, for a while it has had a very slight rough idle which you would only notice buy putting it in park and it becomes smooth as silk. I figured the torque converter was showing age. (145k miles now)
Now I fear the converter is going, but I want to make sure it isn't something simple like low and/or old trans fluid? (which does look low and I need to change this weekend and will do before trying other things), a bad wire? (plugs and wires are Delco but w/90k on them now, though my experience with a bad wire in the past had the miss occurring at speed and underload; not at idle or light load). I have also noticed of late that it fires up very quick when engine is warm/hot; like it has been primed. Sounds like the pressure regulator is starting to leak which eventually will go from 'primed when hot' to 'flooded when hot'. I dont remember, but does a bad pressure reg. do more than just cause hot start probs? Like the surge I have? 'Cause I don't have hot start probs yet.
Related or not, it has been throwing a code (don't know what) for years. It lights up only when you go from a steady cruise in 4th to a slight load, like up a little hill and usually at something like 45 mph. I can keep it from lighting up by getting into the throttle and then letting off. Light goes off upon restarting the car. Won't do it after the car has been on a long trip (like a strong enough vacuum has built up in the gas tank/fuel lines over time) To me, it seems related to fuel pressure/line vacuum related. I wouldn't be surprised if the code was for the fuel cap, though the seal looks good. I remember in the early days the tank would hissss at you when you took the fuel cap off after a looong drive; not for a long time now though.
Hope this isn't too much info!

I had similar symptoms with my Aurora. Rough idle, miss under load, mileage went south..
When is the last time you changed ign. wires and plugs.
My plugs and wires didn't look bad, but After changing mine, It ran like a new car. Miss and rough idle gone

Check it out.

Plugs and wires are on the list. They were replaced by the dealer when I bought the car about 90k ago. I looked at the front wires and saw no signs of streaking and I pulled a few of the front plugs; clean wear, gap at .065 though.
#1 on the list is the fuel pressure reg. as it leaked gas out the vacuum line when I pulled it. So I know this is starting to go.
#2 is the IAC or idle load compensator as it has been 'noisy' for quite a few years. Someone on the N. Amer. Aurora site mentioned removing and cleaning it before paying for replacement. What do I actually clean on it?
#3 is a bad coil. I think I have an ohmmeter to test them, otherwise i have a used coil known to be good.
The 'miss' doesn't sound/feel like the normal abrupt electronic missfire that you can hear in the exhaust....brrrrrrrrr..'Bup!'.brrrrrrrrr.....More of a smooth, rolling surge.
I might just pick up the wires and 4 plugs and do the front cyl bank 'cause its easy. But $$ is tight so i don't want to willy-nilly start throwing $ at it till I find the cause.

my 96 had the same symptoms so i replaced 2 coilovers ran perfect and a month or 2 later same problem started again the i replaced the other 2 and havent had any prob sinece[so just replace all four distirbuterless coils1 might as well replace back 4 plugs and wire while your at it becaose u will have more room 2 work

I do have a known-good coil to swap, but I would like to try testing each coil for resistance but not sure exactly how to do it.

I do have a known-good coil to swap, but I would like to try testing each coil for resistance but not sure exactly how to do it.
Just turn you multi meter to the ohm position and hold a lead on each terminal where the plug wire attaches. Mine have always tested to zero, but I'd think they would be ok if they tested close to zero.

Bob

The primary resistance should be around .4 ohms. The secondary resistance should be around 9,000 ohms.

To primary resistance is checked by measuring the resistance between the two contacts (holes) on the bottom of the coil once it is removed from the ignition control module. The secondary resistance is checked by measuring the resistance between the two terminals on the top of the coil that the spark plug wires connect to.

If your wires have 90k on them then they are most likely your culprit. You cannot determine the condition of the wire via visual inspection. I would not think twice about replacing them if they have 90k on them.

Also, a leaking fuel pressure regulator will not cause the problems you have. It can cause starting issues, but once the car is started its effect on the fuel being put into the engine is minimal compared to the injectors. The oxygen sensor will easily compensate.

Also, there is no reason to skimp on the back plugs. They are very easy to do once the coils and ICM module have been removed.

So I have to have the coils off to test them?

To fully test them you need to take them off. You can test secondary resistance with the coils mounted since that is the resistance between the spark plug wire posts.

Was a bad coil. When i took a second look at the plugs, the #8 (far right up front) plug smelled like gas and was darker than the rest so I figured it wasn't getting good spark. Change coil to known good used coil and all's good. Changed plugs after that,too. Now alternator is whining. Eh, 146k, not bad.