2006 Impreza EJ201 Flat spot at 1750rpm when accelerating
Posted: Sun Nov 08, 2020 2:54 pm
Hello,
2006 Impreza wagon non turbo EJ201 250,000km on the clock.
“Flat” spot at 1750rpm under load
Gutless up hills
Cruise through a roundabout and go to accelerate out - flat spot 1750rpm
Take off at traffic lights - flat spot 1750rpm
Up a steepish incline on a long driveway - flat spot 1750rpm
Take off on the flat - flat spot at 1750rpm
Floor it to get past the flat spot and it eventually jumps to 3000rpm - no in between.
Accelerate quickly when not under load and it sounds like it is gasping for air.
Sitting still with no load, accelerates through the 1750-2000rpm range with a bit of roughness felt through the floor panels, not felt outside that range, but doesn't 'die' like it does under load.
6 months ago:
Scanned O2 sensor bank 1 sensor 1 error. Sensor replaced. Battery disconnected and brake pedal depressed for 10 seconds for computer reset. Ran better for a week then back to the same issues.
Now:
Computer reset has no effect.
No error codes when scanned.
New air filter made no difference.
Catalytic converters in good condition.
Just wondering if anyone else has had this issue and what is the most likely cause?
MAF, plugs, leads, coil, fuel filter (in tank under the rear seat), something else?
Been to 3 mechanics and short of replacing the above items and it “might” fix it, no-one can give me a more specific answer.
Thank-you.
2006 Impreza wagon non turbo EJ201 250,000km on the clock.
“Flat” spot at 1750rpm under load
Gutless up hills
Cruise through a roundabout and go to accelerate out - flat spot 1750rpm
Take off at traffic lights - flat spot 1750rpm
Up a steepish incline on a long driveway - flat spot 1750rpm
Take off on the flat - flat spot at 1750rpm
Floor it to get past the flat spot and it eventually jumps to 3000rpm - no in between.
Accelerate quickly when not under load and it sounds like it is gasping for air.
Sitting still with no load, accelerates through the 1750-2000rpm range with a bit of roughness felt through the floor panels, not felt outside that range, but doesn't 'die' like it does under load.
6 months ago:
Scanned O2 sensor bank 1 sensor 1 error. Sensor replaced. Battery disconnected and brake pedal depressed for 10 seconds for computer reset. Ran better for a week then back to the same issues.
Now:
Computer reset has no effect.
No error codes when scanned.
New air filter made no difference.
Catalytic converters in good condition.
Just wondering if anyone else has had this issue and what is the most likely cause?
MAF, plugs, leads, coil, fuel filter (in tank under the rear seat), something else?
Been to 3 mechanics and short of replacing the above items and it “might” fix it, no-one can give me a more specific answer.
Thank-you.