I have a 97 Riv s/c, I first started having the problem a year ago. During right hand turns or curves the engine stumbles. Also I noticed that it stumbles at negative g's like coming over a hill. it is very intermittent, I tried tracking at different outside air temperatures, gas types, oil types, wet or dry outside, I’ve even gone as far as to see if barometric pressure or dew point makes a difference. I have checked all plugs and plug wires. It is most noticeable when the car is on cruise control or when trying to maintain a speed. The car jerks pretty violently at times at other time it is less violent.
A buddy recommended changing the in-line fuel filter, seeing that I had bought the car at 68k miles and there is 137k on it now and I have never changed it.
Some other information that may help is that the rear valve cover is leaking oil. And it collects around the right rear spark plug (#4 correct?) but I have ensured that no oil is getting in under the spark plug cap and interrupting contact b/w the wire and plug.
I have the GM manuals for my vehicle, and have run through most of the trouble shooting steps for “Surges/Chuggles”.
I am a Flight Engineer so I’m not a mechanical idiot but I essentially have no experience working on cars, so please speak slowly and use small words. :grinyes:

Have you ever changed the wires? Did you change the fuel filter when suggested? This sounds like secondary ignition breakdown i.e. coils, wires or plugs.

No and not yet. i was thinking about replacing the wires (any sugjestions on kind and tips on doing would be great) but i haven't yet. and as soon as it stops raining the new fuel filter is going in. by the way do i need any special tools to bleed the preasure from the fuel rail?

Belden, ACDELCO, MSD wires are the prefered brands. Just do one at a time and it should be fairly easy. The hardest part is getting the boots off the plugs. You will have to twist & pull at the same time. If it don't come loose the first time, take a Bud break & try again. :grinyes:
It could take several Bud's to get all three on the back! :cheers:

Nothing special concerning bleeding the fuel pressure, most people just wrap a shop rag around the valve and bleed it. The proper way is to pull the fuel pump fuse and start the engine, it will bleed pressure as soon as it starts. Be careful if you bleed the rail and don't let it spray in your face! :shakehead (Wear safety glasses):thumbsup:

Ok back from an out of country trip. Before the trip I replaced the O2 sensors, the car finally through a code and a friend with a code reader let me know it was the o2 sensors. And boy did it work great for awhile. Now that I’m back and it is cooling off I noticed it all back again. Looking at the other posts I noticed something about checking and cleaning the idle air control. Did that and it started pretty hard at first. But I got it started on the 3rd attempt and took it down the highway. It ran pretty good, I didn't notice any "chuggling" in the right hand corner but a tiny bit while on cruise. But what was really noticeable was the stumbling that it does when I apply the brake when I slow to 10mph or less. I still didn't change the plug wires, and it one more thing when slowing down and going slow the rpm goes way down then surges. Any more help please?