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blue2oct7 09-01-2011 09:50 PM

Car barely moves when I step on gas pedal!
I have a 1991 legacy wagon. It's been losing power over the last few months. I have to step on the gas pedal very lightly in order to get it to move. If I step on it too hard, the car just laughs at me and doesn't move. I was in a left turn lane the other day (this is the worst incident) and when the light turned green, I barely touched the gas pedal and the car would not crawl more than a couple inches (perhaps that was just the tranny propelling the car forward). I couldn't push the gas lightly, hard, or anywhere in between. I couldn't even rev up the car. It had nothing to give me. Rather than crawl and get stuck in the intersection, I left it there. Husband rescued it 20-30 minutes later and was able to drive it home. I don't know if turning off the car somehow restored some power or if the problem went away. The check engine light came on about a mile or two before I got to that turn lane and stayed on. After exiting the freeway the other day, the check engine light came on, but then turned off almost immediately. The car does not like going up hills either. I have to step on the gas pedal very lightly to get it to down shift.

We tried to read codes unsuccessfully, but will try again. We took off the muffler and catalytic converter, which made no difference in power. I've searched the internet far and wide, with dozens of possible causes coming up. (Of course, I didn't come across any stories very similar to my own.) I'd really like to narrow it down. This is hesitation like I've never heard of or experienced before.

Any ideas?


Legacy Wagon 09-02-2011 05:12 AM

It may be the Mass Air Flow (MAF) sensor. It's part of your intake system and when it goes bad it can bog down the vehicle...even shut it off with bad idling. You can probably pick one up for around $20-30 from a junk yard. Or if you have a friend with a Subaru use theirs and see if it helps.

blue2oct7 09-04-2011 11:20 AM

Luckily, we have a friend with the same car. We exchanged the cam sensor, crank sensor, and mass airflow sensor all without changing our car's behavior. We might exchange knock sensors. Also thinking that maybe the computer itself is bad. Unless it's just a bad engine.

NinjaPablo 09-04-2011 11:36 AM

If the check engine light is on with any consistency, have you tried pulling the OBD blink code? I would be really surprised if the knock sensor was causing the engine to adjust timing that much.

Baddog 09-04-2011 01:12 PM

Check plugs and wires too. See how the plugs are looking. Gives you an inside on what may be happening inside the engine

Legacy Wagon 09-06-2011 05:37 AM

Try using their coil pack while you're at it. At least the sensors you changed out only take a few minutes, but man...that knock sensor's a pain. And it usually doesnt make your car run worse.

rocktown1980 09-07-2011 01:02 PM

I had an 84 olds years ago that was OHC and ran similar to what you describe eventualy it always ran like that. turns out the timing belt was old and streched it eventualy skipped a tooth changing the cam timing. i dont know that this would be your problem but its just a thought.

blue2oct7 09-21-2011 04:31 PM

We finally retrieved codes: 13 (crank angle sensor), 22 (knock sensor), 23 (air flow sensor), 24 (air control valve), and 31 (throttle sensor). Crank & air flow sensors were switched with our friends' sensors. So I don't know if these codes are coming up because they were switched, or because they truly are bad. Each time sensors were switched out, no difference was made with the car. We have new plugs, wires, and coil is fine. Timing belt looks good. The keyway on the crankshaft that hooks the harmonic balancer has a chip on it. Could that be the problem?

Legacy Wagon 09-22-2011 05:15 AM

The woodruff key sticking out of it?
Does your crank pulley wobble?

What's an air control valve? The throttle body?

I'm pretty sure your car wouldnt run without a working crank sensor. The knock sensor shouldnt make it run any worse. At least my old one didnt. The MAF sensor will make it run like crap if it's messed up so that's another easy swap over part that you should try from theirs.

bluescoobgt 09-22-2011 06:44 AM

i would say also if you still have your catalytic converter on the car, have that checked it could cause a major lose in poser if it is bad. i had a 98 transam that would not go over five miles an hour when the cat went bad on it

Legacy Wagon 09-22-2011 01:14 PM

I've heard of that happening too. There's a solution, but most emissions tests wouldnt approve.

blue2oct7 10-31-2011 05:52 PM

Guess what? Problem finally solved!!! We bought a junkyard harmonic balancer, along with that little half-moon-shaped keyway that fits in the notch in the crankshaft, applied JB Weld and it works!!! All this time, the previous damaged keyway was causing the crankshaft to retard the timing! Woo-hoo! Car finally drives like normal!!!

rocktown1980 10-31-2011 11:39 PM

its always nice when its an easy fix like that :)

Legacy Wagon 11-01-2011 05:10 AM

You JB Welded it on? How much? Cause you may still need to get it off there some day. Also it throws off the balance with JB Weld.

blue2oct7 11-02-2011 01:17 PM

All I want is for the damn thing to go when I step on the gas pedal! After experiencing what we've experienced, we'll take our chances! It drives better now than when we first bought it half a year ago.

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