99 Mercury Villager sputtering and back firing

RAYRAY-78

MEMBER
1999 MERCURY VILLAGER
AUTOMATIC
161,000 MILES

I have a 99 mercury villager sport 3.3 liter. Everything has been good untill a few days ago when I was driving down the freeway and it started to sputter a little bit and didnt want to really go when I pushed on the gas pedal. Now it is sputtering really bad and back firing when its in park and you push on gas pedal. We did a full tune up, intake gaskets replaced, vacuum lines replaced, EGR valve good, compression test ok, fuel pressure test ok, map test ok and tps replaced and nothing has changed still doing the same exact thing. Any idea's what can be bad? No check engine lite is on either. Thanks

Wednesday, February 23rd, 2011 AT 10:41 PM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Its gonna be hard to figure this out without the check engine light being on--Possibilities here could be one of the following below-

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing.

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Wednesday, February 23rd, 2011 AT 11:00 PM