'99 Legacy Stalling and Other Issues...

1999 Legacy 2.5L DOHC

4EAT

132,XXX miles.

No mods except for aftermarket rust...

 

Lately, the car once warmed up will intermittenly stall out or stumble at idle unless I tap the gas pedal. When it does idle without stalling, it seems to idle low ~600 RPM. On several (3?) occasions when accelerating from a stop the car would barley move unless I push the pedal all the way down. Then by 5K RPM it may start to take off. Also, when driving at higher speeds (above 40 mph?) it feels like it surges while holding the gas pedal still. I also noticed the gas mileage is horrible. I'm at 150 miles on the trip odometer at 1/2 tank when I'm usually around 200. It also seems that I have burnt some oil as well. No CEL.

 

Approx 2000 miles ago I replaced the following:

 

Plugs

Wires

Air Filter

 

Approx 1000 miles ago I cleaned the MAF as I had a flashing MIL and the car would buck and jerk when accelerating. I forgot the DTC but it was MAF related and would not reset. Afterwards it ran fine until recently.

 

Recently I replaced the fuel filter and PCV valve, and ignition coil (#2 coil was corroded) hoping to help solve my problem. These are things I should have replaced when I did the service but I was being cheap. My next step is front o2 sensor but after that, I'm done throwing parts at it. I need to check the vacuum and maybe do a compression test.

 

Anyone else with similar situation or any thoughts? I'm hoping a flunky front o2 since it seems to start once the vehicle has gone into closed loop. If not, what else could be the cause? Please don't say headgasket.

In order of most likely...

 

1. Clogged catalytic converter?

 

2. Cracked vacuum hose? / Bad PCV Valve?

 

3. O2 Sensors?

 

4. Dirty MAF?

 

5. Worn rings? Scorn cylinder wall?

Thanks for the quick and detailed reply. I posted this on nasioc and nothing. I was in the process of trying to get this car ready to sell or trade in before this happened so all the responses are appreciated.

 

I have the O2 sensor. I'll be changing that this Sat. It's original as far as I know. The MAF is clean but it may still be bad? PCV valve is new. The visual inspection of the vacuum hoses was good. Any hoses in particular to look at?

 

A plugged Cat was my first thought when it didn't want to accelerate. I've only driven one other car with that problem and it was similar but not as pronounced. I'm hoping a bad O2 would do the same? What's the best way to check for a clogged converter? I heard there is some new BS law in CA that you cannot use an aftermarket Cat. My welding skills aren't the best or else I would do it myself if that were the problem.

The best way to see if it's the cat is to unbolt it from the flange and try driving it (Being very mindful of cops, as the car will be LOUD). If it bogs, it's not the cat. If it doesn't bog, it's the cat. Other than that there really isn't a way to check a cat. The reason I think it might be a cat is because when they're clogged the car will generally perform worse once it's warmed up... Which is what you're experiencing.

 

The car could overheat a bit, but if the thermostat works like it should this probably won't be noticeable. If the cat is clogged to the point that there is an exhaust leak somewhere then the exhaust temperature will be significantly lower on the output side of the cat as opposed to the inlet side.

 

What does the exhaust smell like?

Check your Idle Air Control Valve

 

That can cause the surging on the highway, the stumbling/stalling at idle, the low idle, the issue with acceleration, the horrible gas mileage... and yeah. Worth checking out. I'd know because I'm still waiting for a replacement one for my car, lol, have been having all the same issue as you for a few months.

Platinum_Racing: Good info. My exhaust smells ok I guess. I did see a black poof one time when it wouldn't accelerate. I figure it's just dumping unburnt fuel. The tailpipe is kinda sooty as well.

 

Stang70Fastback: I forgot to mention that I need to check the IAC. Did you try cleaning yours before ordering the part? I wasn't sure if that would cause all those problems or get worse once the vehicle was warm.

Update: I drove it 35 miles to my shop. It was surging the whole way at 70mph. It stalled as soon as I stopped off of the fwy.

 

I cleaned the EGR and throttle, replaced the front o2, and cleaned the fuel injectors. I drove it about ten miles. So far so good. *crosses fingers*

Hope for the best!

 

The Idle Air Control might be the problem too. I'd hate to think it's the piston rings, but I've had a similar problem with a Nissan. What was happening was cylinder 1 wouldn't fire all the time. Sometimes the engine would run on all 4 cylinders, and other times it would only run on 3. The car was sitting in my yard for years, and when I finally got my license back I put some parts in it and got it on the road. After a while this problem started happening. The car didn't really cost me anything, so I didn't care... I just drove it till it died. When cylinder 1 stopped firing entirely, I unplugged the fuel injector to save gas. I drove the car on 3 cylinders for 4 months. It was so ghetto... I had a VW wing bolted to the roof, a Master lock on the trunk for the trunk latch, a cherry bomb w/ side pipe for the exhaust, and a hood scoop cut off a lawn tractor welded on the roof. Under the hood I had an MSD Blaster 3 coil with a cold air intake. The intake hose was cracked, so I cut it in half and slapped an old cone filter on it to get it to work right. That was was a POS....

 

If the car sounds funny when it surges then it might be one of the cylinders not firing. The Nissan sounded like a Subaru when it only ran on 3 cylinders. Every so often I'd put some Engine Restore With CSL into the oil and it would run on all 4 for about a hundred miles. You might want to try some of that.

 

Just so you can get an idea of what I was dealing with when I had this car...

http://www.cardomain.com/ride/2957597

 

That was before the MSD ignition and the VW wing, but you get the idea.

 

So yeah, good luck with your car man, let us know how it turns out.

I guess I was too quick to call it a success. It was fine for about 30-40 more miles spread over a 3 trips. Then went back to acting up again. I assume once the ECU recalculated after the reset.

 

It's still running super rich. The fuel trim was -14.5%. I think the EGR may still be bad. It was filthy when I cleaned it. Not as dirty when I reinstalled it. I'm getting the gasket so I can clean the IAC. I'll try an intake flush as well when I get the chance. My co-worker mentioned to check the injectors. I wish if it was running this bad that it would throw me a CEL. The Engine Restore is a good idea.

 

I may try unbolting the cat but it's so rusty that there aren't really any threads left on the studs.

I may try unbolting the cat but it's so rusty that there aren't really any threads left on the studs.

 

This happens pretty often. Unfortunately, if they're that rusted, it's easiest to just cut the bolts/nuts off using a portable metal saw or some sort of reciprocating saw with a really fine toothed metal blade. You don't want to rattle the exhaust around too much.

An impact wrench would probably strip the bolts if its that rusty. I recently replaced my entire muffler from the flange back... pipe and all. It hasd some rust but the impact wrench took the bolts out no problem.

 

Do you have a se of EZ-Outs?

^^^^^^

Yeah, I have a set that I've used too many times on this POS...

Hah!

So the car has been sitting since I bought a new Legacy. I drove it in to work this a.m. and noticed that If I'm driving at a steady freeway speed and begin to go up even a slight incline the trans will kick down unless I'm using cruise. It has almost no power. There is no surging or anything as long as I'm using criuse control. You wouldn't even know there is a problem with it while using cruise.

 

Anyone have any idea why it would drive fine while under cruise control versus using the gas pedal?

Maybe it's because the cruise control holds the throttle steady enough to keep the torque converter locked up. Regardless, the cruise will apply the throttle to maintain speed on the hills, which should kick it into a lower gear anyway.

 

I think you have a Voodoo car.

I'm having the same issue with a 2000 Legacy. Fine on the highway, stalls after warming up at traffic lights and is super slow at take off. Would I expect a check engine light. I changed plugs, wires, timing belt, knock sensor (previous check engine

light.

Also, had replaced head gaskets and the cylinders walls looked great. The car has 177,000 miles...

Funny, I have the same issue in my 97. Only does it after it warms up. Major difference I guess is that mine is a stick and is throwing cylinder misfire codes on cylinder 2 and 3.

Stang70Fastback: I forgot to mention that I need to check the IAC. Did you try cleaning yours before ordering the part? I wasn't sure if that would cause all those problems or get worse once the vehicle was warm.

 

Sorry for the late reply. Yes, I actually soaked it in gas for a long time. However I rinsed it out with water after and attempted to dry it properly, but it seemed to get a little sticky after that so I ended up getting a used one that a friend of mine happened to have...

 

...6 months later, I'm starting to think that one might be acting up as well since sometimes the car idles a bit low at lights, but IDK.

I would look into the MAF first. The MAF is pretty much the highest priority sensor on that car and very easily could cause fuel control issues, and air delivery problems. The IAC valve could cause your idle problem but your also having an off idle throttle surge which almost all the time isnt related to the IAC. This is because the IAC isn't or shouldn't be working to control air flow off idle because your doing that with your foot. Also good rec. on checking the CAT too this is also a likely canidate. Try banging on the CAT when its cold and see if you hear the internals of the cat rattle, if so you need a CAT anyways so change it . If you get to use a scanner ,post some of your at idle and 2k data. It would prob help everyone . Good luck and if you decide to replace the MAF clean the throttle chamber and blade, carbon on the blade can hold it open and throw off the IAC valve and cause a surge