I just had my oil changed

DSCHMITT

MEMBER
1997 MERCURY VILLAGER
140,000 MILES

I just had my oil changed. Now driving the car, my car appears to be chugging or bucking when in low gear, especially seems to be when changing a gear. So I let up on the gas until it runs smooth and just depress slightly until I reach higher speed. It does not do this when in higher speed - just when idle sitting long and starting out from a stop or slow down. Is it a fuel pump, ejector or spark plug problem? Transmission - though it seems to fnd the gear fine? Do I need a tune up? The check engine light is on - but in the past it has gone off and on at different weather changes. All levels are fine. Please help guide me. Thank you.

3 Replies

HANDIONO

MEMBER
3 POSTS

I have very similar problem with my 94 Villager (250K miles). The hesitation / bucking happens during acceleration when the gas pedal is depressed slowly from a stop. When I floor the accelerator, it almost has no problem. It runs fine at high speed and idles fine too. I have replaced throttle position sensor (TPS), front O2 sensor, distributor cap, rotor, spark plugs. Also I have cleaned the mass air flow (MAF). I also removed the vacuum from fuel pressure regulator. Removed the vacuum from EGR valve. None of these fixed the problem. When the engine is hot, the problem diminishes. I had no check engine light. I don't think it is the injectors since it runs fine at high speed and idle. Also runs fine without load at any RPM. I think the engine control system is somehow faulty, but dont know which part causing it.