Has anyone experienced this phenomenon?

Flooring the throttle in a high gear at around 3000 rpm, I get max power/torque for a second, then it drops off slightly for a second...then max power again...then it drops off a bit...and so on up to 4,500 or so revs. After that, she really tramps on.

The effect is as if the car is swaying along as it is accelerating.

My fuel consumption also seems high.

Car is MY99, Scoobysport back box, RAMAIR filter.

I may take it rolling roading, but before I do, has anyone else got any ideas??

Many thanks,

Tony

 

I have experienced, as everyone is now bored to death with, similar problems - now fixed.

I would check the AFM, AFM circuit and fuel pressure as a starter. You can do a self diagnosis using the diagnostic plugs under the steering wheel.

Connect the black ones and turn on the ignition - if you get a code 23 that is the AFM circuit.

Or take it into your dealer...

 

Tony,
Have you had new plugs fitted recently?
I had the exact same symptoms on my MY99 Sti5. It was found that the NGK plugs that were fitted after a service, had too tight a plug gap. This was opened up and then the car ran like a dream.
Subarus are highly sensitive to plug gap changes.

Happy Xmas.
Tim

 

Thanks Rannoch and Tim

I wonder if oil from the filter has b***ered up the sensor?

I'll take it to the dealer, I think.

Rannoch, Mines a UK car, so not sure if the self diagnosis works in the same way. Excuse the ignorance, but where does the error code (eg23) get displayed?

Tim, The problem was there before a 15000 service, but not bad so I didn't mention it and thought the service would pick up anything that was wrong.

I performed an ECU reset thinking it may be a 95RON fuel issue (it had had a couple of tankfuls, whereas I usually run it on 98.

I don't think new plugs come with a 15000 service.

 

Someone posted on IWOC that he had the same problem of hunting and it was down to the ramair filter and took a dealer three days to track it down. I went back to a standard filter (from a ramair) on my last service my hunting went away. I just thought the service had sorted it. I know my local dealers would only remove the ramair as I havent got the PPP. I dont know if it was the removal of the ramair but the car is fine now.

cheers

chrisp

 

Tony,

to do the test see

 

Rannoch,

You are a star..

I'm still at work - Sad - and will be 'til Noon tomorrow.

I'll try the test tomorrow and let you know.

Funny though, seemed to be running perfectly this morning - I'm second guessing, but I wonder if the Ramair Filter occasionally dumps some oil on the hot wire sensor, which I assume is the sensor we're talking about and screws it up for a while. If so, I guess the problem would cease when the oil dissipated. Looking at Chris's reply, this would explain why the problem eventually goes away when the Ramair's removed.

Just thinking out loud, but as Prodrive used to use Ramair filters, I wonder if I could get the sensor replaced under warranty, if it has been damaged by the filter?

Posting soon,

Tony

 

TonyB MY99 has a hot film maf which is particularly sensitive to contamination.

Bob

 

I tried Rannoch's test last night, and got a steady flasshing light, which I believe is an 'all clear'.

I think I'll go back to a standard filter and, if it clears up, consider an induction kit as the free flow option.

Only problem is - like a pr**t, I binned the standard filter (2000 miles) when I got the RAMAIR, so will have to go buy a new one.

Thanks for all the input, guys.

Tony