heres the deal, my 95 auto ran perfect until yesterday, I turned on the air and it started bucking and surging at idle. almost to the point it wanted to stall when you gassed it to take off.
got home, being I was only a few blocks away, turned off the air and it still does it. only in drive, not in park, if it is, you dont notice it.
I let it sit overnight and drove it today, was fine until it got around 140 temp and it started again.
now it feels like just a nasty miss when stopped, you can hear it in park but it dont surge.
I did the search and concluded it to be one of 3 things...

dreaded opti, wires, plugs or possibly a spark module (item 4)

I would just like to get some input on where to start first, being none of these things are cheap or easy.

I am tempted to do everything at once and be done with it, $1200 later for MSD opti and aforementioned parts.

car has 97500 miles on it and still has original packard wires. I am assuming the plugs and opti are also stock.

any input is appreciated. anyone in michigan that would like to help with this daunting task is encouraged to volunteer some time. I am grilling and buying the beer.

EDIT, no codes or check engine light has been activated.

 

took it out for another drive, it has a definite miss. on dead stop acceleration, it has a miss until about 20 MPH but it also has lack luster power and acceleration. used to be excellent pickup and very peppy from a stop, now it seems to be a bit limp wristed.

 

If it was the opti, it wouldnt matter whether the car was warm or not, it would miss consistently.
If it is wires or plugs, a miss could show up once the car ran in closed loop with leaner mixtures.

If it starts doing it immediately after going into closed loop, it might be an O2 sensor, that may or may not throw a code.

My guess based upon the limited information. . . .o2 sensor.

 

my only rebuttal to that would be, it has a DEFINITE miss. upon acceleration, you can feel the miss, car jerks and bucks and then smooths out when you reach a cruise. but if you punch it, it will pull but lacks the "omphfff" it had. it was sudden and did it just after a heavy rain that I was driving in. (co incidence I believe, nothing to do with it)
I was thinking the module for an "all of a sudden" change, but the opti appears dry, is vented and I dont wash the motor to get it wet. it ran like a top until yesterday.
I have had cars with cracked plugs act like this. off and on missing, but it is getting worse everytime I drive it.
I hope it just dies so I can at least have a starting point.

 

injector OHM test shows all injectors between 13.2 and 13.8, put sea foam in the gas, didnt help (late model multec injectors, AKA stock)

 

Your symptoms really sound like a bad plug or wire. I had a cracked plug in my old mustang once, it missed off and on for a couple of months before I found it.

 

I kinda had the same feeling, but I was working my way up from free and getting progressivly more complicated.
I have tons of sea foam laying around for the boat, so I tossed it in, just for ***** and giggles.

 

Yea check your plugs and wires. If there stock the car is 13 years old and time for a changing.

 

I just replaced the cats on my 89.It would run fair when cold but worse when it warmed up.I barely made it home the last time.My right precat was broken up and made it to the main cat.That was cracked in half.I replaced them all and now I'm back to full power.

 

sounds like a dirty fuel filter to me.....if it's the off idle lean hesitation you would get if it were carbed, and the accelerator pump was shot or misadjusted

 

At any rate, your wires are well out of their service life and should be replaced. The O.E.M. Packard wires are only rated for 60,000 miles. You might as well do the plugs, too. (Don't forget the anti-sieze compound for those aluminum heads).

Open your hood at night or in a darkened area of your garage, start the engine, then pull the fuse for the underhood work lamps.

If you've got bad wires, you'll easily see telltale creepycrawlies arcing all over the place!

You can also mist the wires down with a Windex bottle filled with water to scare any electrical gremlins out of hiding, too.

 

I pulled the ignition module and coil and had them tested, they were fine. I am going to do plugs and wires this weekend along with a fuel filter. I belive it to ALL be stock.
it revs all the way up to 5500 but dont seem to have the power, I will be changing everything you members suggested one thing at a time until I find it, but reguardless, the plugs and wire and fuel filter need to be changed. coil, module and opti, only when they fail.
and the cats also, if I get my power back after the first few things, the cats can stay, otherwise, they will be going the way of the dodo also.

 

Can you replace wires without removing the water pump?

 

Hows it running?Is it fixed?

 

well, I wimped out and took it to a local corvette only shop here in flint, (dragos corvette) and they scoped it, turns out, the opti is on the verge of taking a huge crap all over the road.
I will be getting the opti changed next week.

which one should I go with?

GM performance (stock) or MSD?

 

Good time for a cam, EWP, and timing chain replacement.

 

Good idea!

The ol' Fully Automatic Assault Wallet approach. Spray it with parts and cash - it might go away. Wing some cash my way too if ya' got extra in the cash banana clip.

Just an idea, but since it doesn't start till 140' warmed up, maybe a .30 cent piece of straightwire in the right place could fool the computer into thinkin' it always under 140'? Save the $1,200, and send a check to me for $63.95, or somethin' like that?

Maybe even do some diagnostics in that area?

 

well, the garage stuck it on their super secret, ultra high dollar protected by a full time FBI agent corvette scanner\scope.

it showed that the opti was failing and it was causing the miss.
I am only doing the opti, nothing else. I am going to keep it pretty much stock until I get a chance to take it to the dyno gods in detroit for a tune and cam\headers.

only problem is, now it is doing it about 30 seconds after startup, and 80', missing on off light and part throttle. it is only getting worse by the day.

 

Just a thought... Cam swap is about $1000 for labor. Whay pay that twice if they are already going to be in there?

 

I did my Hotcam when I had my opti replaced. I knew they'd be in there anyway and the opti was covered under an extended warranty, so all I had to pay was a little extra for the parts & labor for the cam.