***99 Subaru Legacy Wagon... loss of power and acceleration

[tkt117]

I have a 1999 subaru wagon with 246K miles. ***The car has been a dream,

and has not had any problems other than a bad oil pump and normal

maintenance. ***About 6 months ago the car was experiencing a loss of

power and wouldn't accelerate when I pressed the gas. ***I thought it

needed a tune up. ***After replacing spark plugs the problem persisted.

My mechanic put in on the diagnostic computer and everything checks out okay. ***

 

The problem has gotten really bad recently. ***If I floor the gas the car won't get above 1,500 rpm and sometimes it stalls out completely. ***If I "tap" the gas peddle I can get the rpms as high as I want.

 

We performed all of the obvious test, replaced fuel filter,

checked fuel injectors, check engine compression, checked the MAP

sensor, replaced the oxygen sensor, replaced the ignition coil,

and replaced the timing belt.

 

I have been driving the car for the past six months with this problem,

but it is getting progressively worse. ***Has any one experienced any

thing similar. ***

 

My mechanic thinks it might be the Mass Air flow Sensor. I have heard that the sensor may be bad even though it doesn't send any error codes.

***

We have been swapping sensors between my moms 1996 outback, but the MAF sensor is different. So this one I would have to bite the bullet and actually buy... expenssive trial and error. :-\ Any input would be much appreciated!

 

Thanks

[Snowman]

Have you checked the fuel pressure? How about under load?

 

How about changing the spark plug wires? (Although if it was missing, the check engine light should come on).

[mwatt]

I have a 1999 subaru wagon with 246K miles. ***The car has been a dream,

and has not had any problems other than a bad oil pump and normal

maintenance. ***About 6 months ago the car was experiencing a loss of

power and wouldn't accelerate when I pressed the gas. ***I thought it

needed a tune up. ***After replacing spark plugs the problem persisted.

My mechanic put in on the diagnostic computer and everything checks out okay. ***

 

The problem has gotten really bad recently. ***If I floor the gas the car won't get above 1,500 rpm and sometimes it stalls out completely. ***If I "tap" the gas peddle I can get the rpms as high as I want.

 

We performed all of the obvious test, replaced fuel filter,

checked fuel injectors, check engine compression, checked the MAP

sensor, replaced the oxygen sensor, replaced the ignition coil,

and replaced the timing belt.

 

I have been driving the car for the past six months with this problem,

but it is getting progressively worse. ***Has any one experienced any

thing similar. ***

 

My mechanic thinks it might be the Mass Air flow Sensor. I have heard that the sensor may be bad even though it doesn't send any error codes.

***

We have been swapping sensors between my moms 1996 outback, but the MAF sensor is different. So this one I would have to bite the bullet and actually buy... expenssive trial and error. :-\ Any input would be much appreciated!

 

Thanks

 

I wonder if the catalytic convertor has become restricted or melted-down? That would restrict the flow of exhaust and limit engine rpm. If you have access to a vacuum guage, attach it to one of the intake manifold vacuum ports. Partially open the throttle by hand and watch the vacuum guage. If the vacuum reading continues to drop at a steady 1500 rpm, the catalytic convertor may be plugged up. I've seen technicians disconnect the exhaust ahead of the convertor, then run the engine just for a moment to prove that the convertor is plugged. It'll be loud as hell, but if the engine revs up freely, you've isolated the problem..........

[sea#3]

I have a 1999 subaru wagon with 246K miles. ***The car has been a dream,

and has not had any problems other than a bad oil pump and normal

maintenance. ***About 6 months ago the car was experiencing a loss of

power and wouldn't accelerate when I pressed the gas. ***I thought it

needed a tune up. ***After replacing spark plugs the problem persisted.

My mechanic put in on the diagnostic computer and everything checks out okay. ***

 

The problem has gotten really bad recently. ***If I floor the gas the car won't get above 1,500 rpm and sometimes it stalls out completely. ***If I "tap" the gas peddle I can get the rpms as high as I want.

 

We performed all of the obvious test, replaced fuel filter,

checked fuel injectors, check engine compression, checked the MAP

sensor, replaced the oxygen sensor, replaced the ignition coil,

and replaced the timing belt.

 

I have been driving the car for the past six months with this problem,

but it is getting progressively worse. ***Has any one experienced any

thing similar. ***

 

My mechanic thinks it might be the Mass Air flow Sensor. I have heard that the sensor may be bad even though it doesn't send any error codes.

***

We have been swapping sensors between my moms 1996 outback, but the MAF sensor is different. So this one I would have to bite the bullet and actually buy... expenssive trial and error. :-\ Any input would be much appreciated!

 

Thanks

 

There is a recall on your vehichle for the Mass Air Flow sensor . Take down the VIN# and phone the dealer to see if it's still valid

If it's not reading correctly (not reading the correct amount of air) the ECM won't deliver the right amount of fuel (to lean )

 

SEA#3

[tkt117]

There is a recall on your vehichle for the Mass Air Flow sensor . Take down the VIN# and phone the dealer to see if it's still valid

If it's not reading correctly (not reading the correct amount of air) the ECM won't deliver the right amount of fuel (to lean )

 

SEA#3

 

THANKYOU!!!!! THANK YOU!!!!! THANK YOU!!!!!

 

If you had not posted this message, we would have missed the recall altogether. We checked for recalls in mid November,and didn't even think to check them again....

 

Now we have found the problem, and I have been spared $396.00 in parts!

[diesel_travis]

THANKYOU!!!!! THANK YOU!!!!! THANK YOU!!!!!

 

If you had not posted this message, we would have missed the recall altogether. We checked for recalls in mid November,and didn't even think to check them again....

 

Now we have found the problem, and I have been spared $396.00 in parts!

 

I just experienced this problem recently, but then it magically went away after my car warmed up and hasn't happened since. Is there a place online I can check my VIN or is calling the dealer the only option?

 

Thanks!

[tkt117]

I just experienced this problem recently, but then it magically went away after my car warmed up and hasn't happened since. Is there a place online I can check my VIN or is calling the dealer the only option?

 

Thanks!

 

If you call your dealer and give them your VIN number they will tell you if your car is currently under recall.

 

Here are the symptoms of the MAF sensor.

 

Good Luck! I was thrilled when I found out that I didn't have to pay for it... $400....

 

Mass Air Flow (MAF) Sensor Failure

 

Symptoms:

Unstable idle speed.

Occasional stalling when not in gear.

Constantly high CO (and lambda voltage) at idle. Should oscillate between lean and rich under normal circumstances.

 

Cause: MAF sensor reads too high an air flow on idle, and too low an air flow at high loads. Since the ECU thinks there is more air flow at idle than there really is, it puts in too much fuel, causing an overrich mixture which the ECU cannot compensate for sufficiently. Since the ECU thinks there is less air flow as high loads than there really is, it puts in too little fuel, causing a lean mixture. Since the ECU runs open loop air/fuel ratios at high loads, AFR compensation is not even attempted.

 

Remedy: Replace the air flow sensor ASAP. It is not possible to clean these delicate hot-film sensors effectively. As the sensor deteriorates, mixtures become leaner, eventually causing damage to the engine due to det and high temperatures. As a short term fix, raise the idle speed, use a high octane fuel and keep engine revs as low as possible while driving.

[jontyuk]

Just experianced a faulty Mass air flow sensor on my 98 2.5 legacy. I noticed a slight engine hesitation and then the engine check light came on. A further five miles on the engine cut out and I had to pull into the side. On attempting to re-start, the engine would fire but sounded if it was running on two cylinders and then stopped. I had to call recovery and the mechanic could not fix it.

The vehicle was then taken to the local Subaru Dealer who diagnosed a faulty Mass air flow sensor which set me back £320 (approx $470) for parts and labour. the recovery was covered by my insurance.

 

Does anyone know if a failure such as this, on a part that was on a recall list, is eligable for a retrospective repayment? Or as I suspect, I have no chance!!