Oldsmobile/Buick Repair: 98 LeSabre Stalling, egr valve, driveability concerns

Question
I have a 98 Buick LeSabre 3.8L V6 with A/C. Lately, I've had a problem with stalling or bucking. It always seems to happen at the same time (same intersections or distances) after about 3 minutes from starting. It does it after it hasn't run for more than an hour or so. If I stop or am slowing down, it stalls. If I'm driving at any speed over 10MPH, it bucks like it's going to stall, but then runs fine for the duration of the trip. It bucks real hard at high speeds on the highways. It does it with or without the A/C on. No warning lights come on, except the usual after it stalls. It usually starts right back up after a stall and then runs OK, with mild idle fluctuations. Gradually getting worse. Sometimes stalls 2 or 3 times now. 96,000 miles. Just replaced spark plugs 6,000 miles ago (good for 100,000). Just replaced air filter. New starter.

Answer
hi jason.and thanks for such a theral explanation of of the driveability concerns on your vehicle.two things come to mind #1 egr valve will cause a stall or stumble and the drive time can be exactly the same .due to the heat of the eng temp will usually be the same.#2 is a plug or wire miss ,however normally will not cause a stall.only a miss.a bad egr valve actually causes a open vacum.and will act differently in diff temps.so check this out if it don,t work get back with me but you may want to have your scanned to confirm this before repair as this part is kinda priceie.please take a sec to rate my help ty billymac