I have a 2002 Subaru Legacy L wagon, nicknamed the ‘Wedgie’. Over the last month, I’ve had a problem with the check engine light coming on when I go around a certain exit ramp off the highway - it’s an abrupt sharp circle. The light comes on, then my car shakes like it will stall after I’ve come to a stop. The shaking goes away when I start to accelerate. Then a day or two later the light will pop off. This cycle repeats every couple of days, always after slowing down around the same ramp. Today the car actually stalled on me when I was stopped at a light after pulling off said ramp. I made an appointment at the dealer, but of course, as soon as I pulled in, the light went back off and they could not diagnose anything. Any ideas?
Just how close to empty is your gas tank ?
Today was the first time it stalled, and the tank is at 3/4 full. I keep it at 1/2 tank full and above at all times.
ok…scratch idea # 1.
I wonder if this happens,( and you just havent noticed as such ), when the accelerator is let off abruptly -vs- a gradual deceleration. For example slowing for a red light compared to 30mph-off the gas- onto the brake ? Test this theory while driving.
Forgot to mention it’s a five-speed, and yes, I do know how to shift properly. The stall was very gentle…like the fuel was cutoff?
I’ve tried slowing just by downshifting, with braking/downshifting, and just letting off the gas (to the point where I need to downshift), and I don’t notice any differences - either way yeilds the same result. And no shakiness until I’ve gone around the ramp. hmm.
Next theory…( re; why does centrifugal force seem to matter ? ) On this corner does the fuel slosh up to the side of the tank where the vapor return connection is, thereby cuasing a vacuum problem by ingesting a taste of gas ? Is this a saddle type tank where the fuel could slosh mostly to one side and temporarily starve the fuel pickup tube ?
I’m going to suggest you carefully inspect the air intake and vacuum hoses for leaks. Check the intake manifold to ensure the bolts are torqued to specs.
When the light came on, a “trouble code” was set. The dealer should have checked the codes and figured out what caused the problem. Next time it happens, most auto-parts stores will read the codes for you free and tell you what they mean…The code stays set even though the light goes off.
It sounds to me like fuel starvation, or a fuel pressure issue. Fuel should not slosh around enough to leave the suction pickup dry- there’s a baffle that the pump sits in that prevents this from happening.
Another possibility is that somehow fuel is getting into the evap system.
The OBD codes would be helpful here.
Crazy idea- since you know how to trigger it, have someone with a scantool scan the car immediately after you trigger it. Or, drive right to an Autozone after you trigger it and have them scan it for free right there.
I did that last night, and the tech told me it was an idle control code? Could an idling problem be made worse by going around a sharp turn, or having to slow down from high speeds abruptly? I paid close attenetion to my idle while driving this morning, and it was steady when stopped at about 500 rpm.
Having the exact code would be helpful- it’ll be in the format Pnnnn, where nnnn are numbers.
500 RPM seems like a very low idle, though I have no idea what is spec on thsi car, but that would be something to look at.