MY01 Acceleration/Fuel Troubles

breaker1845 · Post by **breaker1845** » Mon Apr 14, 2014 5:40 pm

Hi all,

Just recently my N/A MY01 Impreza RX has developed a problem which has only just been noticeable. While driving/accelerating if you try to go beyond 4k rpm for some reason (i.e. overtaking) the car seems to cut fuel to the engine as if it was operating in Limp Mode. The only way to get rid of the problem is to obviously take your foot off the throttle and slow down or change gears.

I have tried a few things listed below to see if it could fix the issue:
- I have done a service including new spark plugs and air filter as I thought the car might be misfiring at the top end or not enough air flow.
- I have cleaned out the throttle body with carby cleaner and done an upper engine clean which didn't really help.
- I have checked for ECU code faults and there were none which indicates all the sensors are operating correctly or not throwing fault codes.
- I have installed a new radiator recently so overheating is not an issue.

Basically the car seems to lose power from 3.5k rpm onwards and if you put the throttle to the ground the car seems to just stop injecting fuel into the engine. Imagine going rolling speed with your clutch all the way out and no acceleration that is what it feels like but at approximately 4k rpm. It happens in all gears from first to fifth.

I am thinking it is some kind of blockage somewhere within the car. The next thing would be fuel issues but I don't want to go ahead and check it out yet until I can narrow down the problem as time is limited at the moment.

Just curious on people's thoughts and suggestions as I haven't dealt with this kind of issue before on my Subaru. This is a N/A car as mentioned so there is no boost leaks and the usual that people usually encounter on turbo charged models.

Any help would be appreciated and more information can be supplied on request. The car is still in a drivable condition but I don't like to have it running in the current condition.

Cheers

outback · Post by **outback** » Mon Apr 14, 2014 6:53 pm

I could be wrong but it does sound like a fuel filter prob.
That would be the first thing I'd look at.

taza · Post by **taza** » Mon Apr 14, 2014 8:41 pm

Replace fuel filter, either in tank or engine bay (possibly both?).
Check spark plug's condition, replace if necessary.
Check air filter, replace if necessary.
Take to auto electrician as it could be posaible map/maf sensor. They will be able to moitor sensor/s on a scan tool.
I had a sinilar problem with a Toyota Echo today at work.

Remember start with the basics