check engine light?
my check engine remain on my dashboard, I change the oxygen sensor and egr valve but the light still remain on

The Toyota Previa saw a few important changes in 1994. To answer consumers’ complaints that the Previa was underpowered, Toyota offered a supercharged version of its upscale LE model. The Previa also got a redesigned front bumper, spoiler, and front seats.
The 1994 Previa came in six trims: the DLX, the DLX AllTrac, the LE, the LE AllTrac, the supercharged LE, and the supercharged LE AllTrac. The base engine was a 2.8-liter, 138 horsepower four-cylinder. The supercharged engine made 161 horsepower. Fuel economy was about 17/21 mpg. The 1994 Previa sat seven people, and had the option of captains’ chairs in the second row instead of a bench.
The 1994 Toyota Previa was well liked for its excellent handling, futuristic dashboard, ample cargo and legroom, unique styling, and reliability. Despite the availability of a supercharged engine, many drivers still found themselves wishing for a V6.
my check engine remain on my dashboard, I change the oxygen sensor and egr valve but the light still remain on
Is the engine which is a 4 cylinder an interference engine
Help Please: I was driving my van last weekend and it just died out, no warning sign what so ever. The van said âyour not going anywhere today buddyâ. It will start up again at any time, the problem is that it only stays on for 3-4 seconds. It does no difference if I step on the gas to try to keep it going, itâs like not registering that command. I replaced the fuel pump because a friend suguested that was the most likely culprit but problem is still the same (the gas filter was replaced in mid summer) .Itâs not staying on long enough to register any trouble codes (I have an OBDII scanner). I checked the fuse & most of the relays (main relay, EFI relay, fuel pump relay, function relay?). I have been Poking here & there after work and notice the Air filter some what dirty and replaced it. Now it starts and stays ON a few seconds longer starts to idle rough, bucks, hesitate and dies. About the 3rd attempt, I did revved it up upon start-up and it did hold high rpm but when I left go the gas it hesitated and died. It was late and cold and the battery lost itâs charge, so I went inside with my head down with still no clue. Need some straight forward advice on this one. Thank you for your time
why is the battery go dead
Airbags
Dual front airbags
Audio System
Single disc in-Dash CD · AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: bench
Roof
OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: cloth
Third Row Seat
Type: 50-50 split bench
Windows
Front wipers: intermittent
Airbags
Dual front airbags
Audio System
AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: bench
Roof
OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: cloth
Third Row Seat
Type: 50-50 split bench
Windows
Front wipers: intermittent
Airbags
Dual front airbags
Audio System
Single disc in-Dash CD · AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: captains chairs
Roof
Moonroof: power · OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: cloth
Third Row Seat
Type: 50-50 split bench
Tires and Rims
Wheels: alloy
Windows
Front wipers: intermittent
Airbags
Dual front airbags
Audio System
Single disc in-Dash CD · AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: captains chairs
Roof
Moonroof: power · OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: cloth
Third Row Seat
Type: 50-50 split bench
Tires and Rims
Wheels: alloy
Windows
Front wipers: intermittent
Airbags
Dual front airbags
Audio System
Single disc in-Dash CD · AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: bench
Roof
OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: leather
Third Row Seat
Type: 50-50 split bench
Tires and Rims
Wheels: alloy
Windows
Front wipers: intermittent
Airbags
Dual front airbags
Audio System
Single disc in-Dash CD · AM/FM radio
Brakes
ABS: 4-wheel
Convenience Features
Steering wheel: tilt-adjustable
Mirrors
Exterior mirrors: power
Rear Seats
Type: captains chairs
Roof
OEM roof height: undefined
Seats
Front seat type: bucket · Upholstery: cloth
Third Row Seat
Type: 50-50 split bench
Tires and Rims
Wheels: alloy
Windows
Front wipers: intermittent