Anybody ever have a problem with their car backfiring? I have a stock (K&N panel, off road h pipe and flows) 89 lx with 184,000 miles. Never had to do anything to it major; change the oil every 3000 miles, have the alt. rebuilt, new water pump, fuel pump, and minor tune up parts and brakes through the years. Over the past couple months, its started backfiring. It only does it when I past a car or anytime I run the rpm up (under a load, not with the car sitting in the driveway) to around 4500 - 5500 ( all this WOT), then press the clutch in to change gears and POW!!! Its load, and at night you can see some flame come out the tail pipe. I replaced the 02 sensors with some advance auto Bosch units ( I usually use Ford parts, but I went cheap this time, I figured they where made by the same company), this didn't help. Other than the backfiring, the car runs great; no skipping at any rpm, no hesitation, no check engine lights, same fuel milage, it runs the same as it ever has. I'm baffled. If anyone has any ideas, please let me know. Thanks