Hey guys, I have a baffling one for y'all.

I have a 1994 SLE with 120k. The engine will sputter and sputter intermittently ( but more common than not) at idling speeds, the engine will go up and down by about 500 RPM each way. The car has perfect power at higher RPMs, and doesn't stutter at all or even have a loss of power.

It *first* happened when I took a corner very tightly. At the beginning of the problem, It would NOT stay started, even when I rammed hard on the throttle. I had to "pop the clutch" at high RPMs to get it moving. Things improved drastically after I threw a bottle of red HEET into the engine, and I've already run 2 tanks of 93 through it, and I've still got these problems.

The car *has* had persistent electrical problems. It is now on its sixth alternator and fourth battery, I could go on and on and rant a bit about GMPP but I will suffice it to say that these issues were not solved while under the 6 year 100k extended warranty. But, I digress.

What we've done so far:
Replace Alternator (had a bit of a drain)
Plugs (Bosch plat 4) are ok.
Plug wires were replaced at 70k with some high quality wires.
(we couldn't find the PCV valve to replace, a SEARCH will solve this)
Put on new vacuum hoses on a few hoses that looked a bit frayed.

Any help that you guys would be able to give would be greatly appreciated.

The first thing I would check is your Bosch plugs to see if they are full of gas. I ran Bosch plugs once and had nothing but trouble with them. If I where you I would consider replaceing your plugs with stock plugs or do a search to see what other members are running for plugs.-Toddster

Oh, and welcome to the Bonneville Club

Thanks for the fast reply, and for the welcome, Toddster. The Bosch plugs are about 50k old, and appear to be rather evenly burned / aged.

Bosch stuff dosnet agree with our cars.....are there any codes thrown?

In addition to the Bosch plugs not seeming to be agreeable with our cars, Taylor brand wires haev been known to be bad too. I think your on the right track checking the PCV valve.

You also mention electrical problems...check all battery cable connections for corrosion.

Have you ever had a water leak?...wet carpets?...there are ground connectors that may also need a good cleaning.

How old is the fuel pump? Are the coil packs original?

Any Check Engine lights?

I took it in to a local Auto Zone store. Had a former GM employee looking at it. HE was surprised that it had a thing to plug the code detector in under the steering column. Anyways, he stuck in something that looked like (a golf divot repairer with two prongs) and he also tried a code reader that had a full digital display. Unfortunately, it would *NOT* give me any codes, as I said to him, I've had persistent electrical problems, and he said, "there ya go." So, unfortunately, I have no codes to give :(

Wow, you guys are fantastically helpful. Let me go answer these one by one.

1) We're checking the PCV valve tomorrow. It'* night time right now and raining yuxxor.

2) No mentionable corrosion on the battery cable connections.

3) I've never had a water leak in the car, although I've spilled quite a few coffees :wink

4) The fuel pump is, if I'm not mistaken, younger than 3 years old. The coil packs are 100% original (and 12 years old)

And, again, thanks for all of your advice.

Whoops, I almost forgot. I do get the Check Engine Soon light most of the time. Occasionally when I start it up, the idle speed is FINE, but inevitably within one minute the idle will start stuttering and sputtering and the Check Engine Soon light will come on. Oddly enough, which I forgot to mention, is that the Traction Control light also tends to light up at the same time that this happens.

It sounds like it'* gulping and excessive amount of air but the engine RPM does not increase. It'* just so danged odd. You know, I absolutely LOVED this car the first 3 years that I had it, until GM spit in my face and was 100% wrong with the problems and ... nevermind.

if the SES is on there is a code....go to an advance....they can read your car...you have a OBD1/2, its a hybrid year that uses the OBDII cabel and the OBDI codes.... try and get is scanned

I'll do that first thing tomorrow in the AM. Thanks for your overwhelming help!