Engine appears to idle ok. Hesitation/misfiring present during acceleration. At steady speed, sudden temporary RPM drop occurs - sometimes causing significant " jerk" - and return to normal operation. Occurs more frequently and more violently after engine warms up (every 10 sec or so once warm at steady speed).
Am about to get under the hood, any pointers would be appreciated! : D
My 1998 Lincoln Continental (81,000 miles) is doing the exact same thing. I took it to pepboys and had them put it on the computer, but nothing showed up. NOW, my check engine light is coming on and I cant drive it back to let them re-run the computer diagnosis because my car will not go faster than 20 mph!
I disconnected my front oxygen sensor, and it did not improve nor worsen. I reconnected that one, and unhooked the back one (seems I have 2 oxygen sensors) and it ran worse.
So, at this phase of the game I am assuming that because the performance did not worsen removing the first, nor did it make it better, my front oxygen sensor is faulty. But at 57$ a pop I HAVE to be sure.
I checked my catalytic converter, I have plenty of exhaust and no rattles coming from inside of it when I tapped on it. I disconnected my EGR Valve with no change (good or bad). Tune up was performed at 61,000 miles.
When this problem first showed up, I was exitting the freeway and when I came to the stop sign it was like there was too much gas. Choking it out. Then it started spitting and sputtering going down the road. It sounded like it wanted to backfire but was not popping like a gun, its pop was more like a muffled sound and I could feel the vibration from this sputter under the car in the middle. Upon looking under my car, the only thing I noticed when the car was running and sputtering, the exhaust has a acordian piece that expands (elongates) when you give it gas. Grrrrrrrrrrr I am a single mom, someone.